From 8876fe0813ed39350df4e3565fb5943cff2a6237 Mon Sep 17 00:00:00 2001 From: rgallard Date: Fri, 17 Oct 2014 11:33:22 -0700 Subject: [PATCH] 8060151: Check-in changes for 8u40 nroff Open JDK Reviewed-by: mcimadamore, kvn --- src/bsd/doc/man/java.1 | 5211 ++++++++------------- src/bsd/doc/man/javac.1 | 3230 +++++-------- src/bsd/doc/man/javadoc.1 | 224 +- src/bsd/doc/man/jjs.1 | 33 +- src/bsd/doc/man/jstat.1 | 177 +- src/bsd/doc/man/keytool.1 | 426 +- src/bsd/doc/man/policytool.1 | 8 +- src/linux/doc/man/java.1 | 5211 ++++++++------------- src/linux/doc/man/javac.1 | 3230 +++++-------- src/linux/doc/man/javadoc.1 | 224 +- src/linux/doc/man/jjs.1 | 33 +- src/linux/doc/man/jstat.1 | 177 +- src/linux/doc/man/keytool.1 | 426 +- src/linux/doc/man/policytool.1 | 8 +- src/solaris/doc/sun/man/man1/java.1 | 5211 ++++++++------------- src/solaris/doc/sun/man/man1/javac.1 | 3230 +++++-------- src/solaris/doc/sun/man/man1/javadoc.1 | 224 +- src/solaris/doc/sun/man/man1/jjs.1 | 33 +- src/solaris/doc/sun/man/man1/jstat.1 | 177 +- src/solaris/doc/sun/man/man1/keytool.1 | 426 +- src/solaris/doc/sun/man/man1/policytool.1 | 8 +- 21 files changed, 11472 insertions(+), 16455 deletions(-) diff --git a/src/bsd/doc/man/java.1 b/src/bsd/doc/man/java.1 index bc8f1f105..552dd48a1 100644 --- a/src/bsd/doc/man/java.1 +++ b/src/bsd/doc/man/java.1 @@ -1,3461 +1,2198 @@ '\" t -.\" Copyright (c) 1994, 2014, Oracle and/or its affiliates. All rights reserved. -.\" -.\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. -.\" -.\" This code is free software; you can redistribute it and/or modify it -.\" under the terms of the GNU General Public License version 2 only, as -.\" published by the Free Software Foundation. -.\" -.\" This code is distributed in the hope that it will be useful, but WITHOUT -.\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or -.\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -.\" version 2 for more details (a copy is included in the LICENSE file that -.\" accompanied this code). -.\" -.\" You should have received a copy of the GNU General Public License version -.\" 2 along with this work; if not, write to the Free Software Foundation, -.\" Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. -.\" -.\" Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA -.\" or visit www.oracle.com if you need additional information or have any -.\" questions. -.\" -.\" Title: java -.\" Language: English -.\" Date: 08 August 2014 -.\" SectDesc: Basic Tools -.\" Software: JDK 8 -.\" Arch: generic -.\" Part Number: E38207-03 +.\" Copyright (c) 1994, 2015, Oracle and/or its affiliates. All rights reserved. +.\" +.\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. +.\" +.\" This code is free software; you can redistribute it and/or modify it +.\" under the terms of the GNU General Public License version 2 only, as +.\" published by the Free Software Foundation. +.\" +.\" This code is distributed in the hope that it will be useful, but WITHOUT +.\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or +.\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +.\" version 2 for more details (a copy is included in the LICENSE file that +.\" accompanied this code). +.\" +.\" You should have received a copy of the GNU General Public License version +.\" 2 along with this work; if not, write to the Free Software Foundation, +.\" Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. +.\" +.\" Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA +.\" or visit www.oracle.com if you need additional information or have any +.\" questions. +.\" +.\" Arch: generic +.\" Software: JDK 8 +.\" Date: 03 March 2015 +.\" SectDesc: Basic Tools +.\" Title: java.1 .\" .if n .pl 99999 -.TH "java" "1" "08 August 2014" "JDK 8" "Basic Tools" -.\" ----------------------------------------------------------------- -.\" * Define some portability stuff -.\" ----------------------------------------------------------------- -.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -.\" http://bugs.debian.org/507673 -.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html -.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -.ie \n(.g .ds Aq \(aq -.el .ds Aq ' -.\" ----------------------------------------------------------------- -.\" * set default formatting -.\" ----------------------------------------------------------------- -.\" disable hyphenation -.nh -.\" disable justification (adjust text to left margin only) -.ad l -.\" ----------------------------------------------------------------- -.\" * MAIN CONTENT STARTS HERE * -.\" ----------------------------------------------------------------- -.SH "NAME" +.TH java 1 "03 March 2015" "JDK 8" "Basic Tools" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- + +.SH NAME java \- Launches a Java application\&. -.SH "SYNOPSIS" -.sp -.if n \{\ -.RS 4 -.\} -.nf +.SH SYNOPSIS +.sp +.nf + \fBjava\fR [\fIoptions\fR] \fIclassname\fR [\fIargs\fR] -.fi -.if n \{\ -.RE -.\} -.sp -.if n \{\ -.RS 4 -.\} -.nf +.fi +.nf + \fBjava\fR [\fIoptions\fR] \fB\-jar\fR \fIfilename\fR [\fIargs\fR] -.fi -.if n \{\ -.RE -.\} -.PP +.fi +.sp +.TP \fIoptions\fR -.RS 4 -Command\-line options separated by spaces\&. See Options\&. -.RE -.PP +Command-line options separated by spaces\&. See Options\&. +.TP \fIclassname\fR -.RS 4 The name of the class to be launched\&. -.RE -.PP +.TP \fIfilename\fR -.RS 4 -The name of the Java Archive (JAR) file to be called\&. Used only with the -\fB\-jar\fR -option\&. -.RE -.PP +The name of the Java Archive (JAR) file to be called\&. Used only with the \f3-jar\fR option\&. +.TP \fIargs\fR -.RS 4 -The arguments passed to the -\fBmain()\fR -method separated by spaces\&. -.RE -.SH "DESCRIPTION" -.PP -The -\fBjava\fR -command starts a Java application\&. It does this by starting the Java Runtime Environment (JRE), loading the specified class, and calling that class\*(Aqs -\fBmain()\fR -method\&. The method must be declared -\fIpublic\fR -and -\fIstatic\fR, it must not return any value, and it must accept a -\fBString\fR -array as a parameter\&. The method declaration has the following form: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBpublic static void main(String[] args)\fR - -.fi -.if n \{\ -.RE -.\} -.PP -The -\fBjava\fR -command can be used to launch a JavaFX application by loading a class that either has a -\fBmain()\fR -method or that extends -\fBjavafx\&.application\&.Application\fR\&. In the latter case, the launcher constructs an instance of the -\fBApplication\fR -class, calls its -\fBinit()\fR -method, and then calls the -\fBstart(javafx\&.stage\&.Stage)\fR -method\&. -.PP -By default, the first argument that is not an option of the -\fBjava\fR -command is the fully qualified name of the class to be called\&. If the -\fB\-jar\fR -option is specified, its argument is the name of the JAR file containing class and resource files for the application\&. The startup class must be indicated by the -\fBMain\-Class\fR -manifest header in its source code\&. +The arguments passed to the \f3main()\fR method separated by spaces\&. +.SH DESCRIPTION +The \f3java\fR command starts a Java application\&. It does this by starting the Java Runtime Environment (JRE), loading the specified class, and calling that class\&'s \f3main()\fR method\&. The method must be declared \fIpublic\fR and \fIstatic\fR, it must not return any value, and it must accept a \f3String\fR array as a parameter\&. The method declaration has the following form: +.sp +.nf +\f3public static void main(String[] args)\fP +.fi +.nf +\f3\fP +.fi +.sp +The \f3java\fR command can be used to launch a JavaFX application by loading a class that either has a \f3main()\fR method or that extends \f3javafx\&.application\&.Application\fR\&. In the latter case, the launcher constructs an instance of the \f3Application\fR class, calls its \f3init()\fR method, and then calls the \f3start(javafx\&.stage\&.Stage)\fR method\&. +.PP +By default, the first argument that is not an option of the \f3java\fR command is the fully qualified name of the class to be called\&. If the \f3-jar\fR option is specified, its argument is the name of the JAR file containing class and resource files for the application\&. The startup class must be indicated by the \f3Main-Class\fR manifest header in its source code\&. .PP The JRE searches for the startup class (and other classes used by the application) in three sets of locations: the bootstrap class path, the installed extensions, and the user\(cqs class path\&. .PP -Arguments after the class file name or the JAR file name are passed to the -\fBmain()\fR -method\&. -.SH "OPTIONS" -.PP -The -\fBjava\fR -command supports a wide range of options that can be divided into the following categories: -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +Arguments after the class file name or the JAR file name are passed to the \f3main()\fR method\&. +.SH OPTIONS +The \f3java\fR command supports a wide range of options that can be divided into the following categories: +.TP 0.2i +\(bu Standard Options -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Non\-Standard Options -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu +Non-Standard Options +.TP 0.2i +\(bu Advanced Runtime Options -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu Advanced JIT Compiler Options -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu Advanced Serviceability Options -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu Advanced Garbage Collection Options -.RE .PP Standard options are guaranteed to be supported by all implementations of the Java Virtual Machine (JVM)\&. They are used for common actions, such as checking the version of the JRE, setting the class path, enabling verbose output, and so on\&. .PP -Non\-standard options are general purpose options that are specific to the Java HotSpot Virtual Machine, so they are not guaranteed to be supported by all JVM implementations, and are subject to change\&. These options start with -\fB\-X\fR\&. +Non-standard options are general purpose options that are specific to the Java HotSpot Virtual Machine, so they are not guaranteed to be supported by all JVM implementations, and are subject to change\&. These options start with \f3-X\fR\&. .PP -Advanced options are not recommended for casual use\&. These are developer options used for tuning specific areas of the Java HotSpot Virtual Machine operation that often have specific system requirements and may require privileged access to system configuration parameters\&. They are also not guaranteed to be supported by all JVM implementations, and are subject to change\&. Advanced options start with -\fB\-XX\fR\&. +Advanced options are not recommended for casual use\&. These are developer options used for tuning specific areas of the Java HotSpot Virtual Machine operation that often have specific system requirements and may require privileged access to system configuration parameters\&. They are also not guaranteed to be supported by all JVM implementations, and are subject to change\&. Advanced options start with \f3-XX\fR\&. .PP To keep track of the options that were deprecated or removed in the latest release, there is a section named Deprecated and Removed Options at the end of the document\&. .PP -Boolean options are used to either enable a feature that is disabled by default or disable a feature that is enabled by default\&. Such options do not require a parameter\&. Boolean -\fB\-XX\fR -options are enabled using the plus sign (\fB\-XX:+\fR\fIOptionName\fR) and disabled using the minus sign (\fB\-XX:\-\fR\fIOptionName\fR)\&. -.PP -For options that require an argument, the argument may be separated from the option name by a space, a colon (:), or an equal sign (=), or the argument may directly follow the option (the exact syntax differs for each option)\&. If you are expected to specify the size in bytes, you can use no suffix, or use the suffix -\fBk\fR -or -\fBK\fR -for kilobytes (KB), -\fBm\fR -or -\fBM\fR -for megabytes (MB), -\fBg\fR -or -\fBG\fR -for gigabytes (GB)\&. For example, to set the size to 8 GB, you can specify either -\fB8g\fR, -\fB8192m\fR, -\fB8388608k\fR, or -\fB8589934592\fR -as the argument\&. If you are expected to specify the percentage, use a number from 0 to 1 (for example, specify -\fB0\&.25\fR -for 25%)\&. -.SS "Standard Options" +Boolean options are used to either enable a feature that is disabled by default or disable a feature that is enabled by default\&. Such options do not require a parameter\&. Boolean \f3-XX\fR options are enabled using the plus sign (\f3-XX:+\fR\fIOptionName\fR) and disabled using the minus sign (\f3-XX:-\fR\fIOptionName\fR)\&. .PP +For options that require an argument, the argument may be separated from the option name by a space, a colon (:), or an equal sign (=), or the argument may directly follow the option (the exact syntax differs for each option)\&. If you are expected to specify the size in bytes, you can use no suffix, or use the suffix \f3k\fR or \f3K\fR for kilobytes (KB), \f3m\fR or \f3M\fR for megabytes (MB), \f3g\fR or \f3G\fR for gigabytes (GB)\&. For example, to set the size to 8 GB, you can specify either \f38g\fR, \f38192m\fR, \f38388608k\fR, or \f38589934592\fR as the argument\&. If you are expected to specify the percentage, use a number from 0 to 1 (for example, specify \f30\&.25\fR for 25%)\&. +.SS STANDARD\ OPTIONS These are the most commonly used options that are supported by all implementations of the JVM\&. -.PP -\-agentlib:\fIlibname\fR[=\fIoptions\fR] -.RS 4 -Loads the specified native agent library\&. After the library name, a comma\-separated list of options specific to the library can be used\&. -.sp -If the option -\fB\-agentlib:foo\fR -is specified, then the JVM attempts to load the library named -\fBlibfoo\&.so\fR -in the location specified by the -\fBLD_LIBRARY_PATH\fR -system variable (on OS X this variable is -\fBDYLD_LIBRARY_PATH\fR)\&. -.sp +.TP +-agentlib:\fIlibname\fR[=\fIoptions\fR] +.br +Loads the specified native agent library\&. After the library name, a comma-separated list of options specific to the library can be used\&. + +If the option \f3-agentlib:foo\fR is specified, then the JVM attempts to load the library named \f3libfoo\&.so\fR in the location specified by the \f3LD_LIBRARY_PATH\fR system variable (on OS X this variable is \f3DYLD_LIBRARY_PATH\fR)\&. + The following example shows how to load the heap profiling tool (HPROF) library and get sample CPU information every 20 ms, with a stack depth of 3: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-agentlib:hprof=cpu=samples,interval=20,depth=3\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3\-agentlib:hprof=cpu=samples,interval=20,depth=3\fP +.fi +.nf +\f3\fP +.fi +.sp + + The following example shows how to load the Java Debug Wire Protocol (JDWP) library and listen for the socket connection on port 8000, suspending the JVM before the main class loads: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-agentlib:jdwp=transport=dt_socket,server=y,address=8000\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3\-agentlib:jdwp=transport=dt_socket,server=y,address=8000\fP +.fi +.nf +\f3\fP +.fi +.sp + + For more information about the native agent libraries, refer to the following: -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -The -\fBjava\&.lang\&.instrument\fR -package description at http://docs\&.oracle\&.com/javase/8/docs/api/java/lang/instrument/package\-summary\&.html -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.RS +.TP 0.2i +\(bu +The \f3java\&.lang\&.instrument\fR package description at http://docs\&.oracle\&.com/javase/8/docs/api/java/lang/instrument/package-summary\&.html +.TP 0.2i +\(bu Agent Command Line Options in the JVM Tools Interface guide at http://docs\&.oracle\&.com/javase/8/docs/platform/jvmti/jvmti\&.html#starting -.RE -.RE -.PP -\-agentpath:\fIpathname\fR[=\fIoptions\fR] -.RS 4 -Loads the native agent library specified by the absolute path name\&. This option is equivalent to -\fB\-agentlib\fR -but uses the full path and file name of the library\&. -.RE -.PP -\-client -.RS 4 -Selects the Java HotSpot Client VM\&. The 64\-bit version of the Java SE Development Kit (JDK) currently ignores this option and instead uses the Server JVM\&. -.sp -For default JVM selection, see Server\-Class Machine Detection at - -http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/server\-class\&.html -.RE -.PP -\-D\fIproperty\fR=\fIvalue\fR -.RS 4 -Sets a system property value\&. The -\fIproperty\fR -variable is a string with no spaces that represents the name of the property\&. The -\fIvalue\fR -variable is a string that represents the value of the property\&. If -\fIvalue\fR -is a string with spaces, then enclose it in quotation marks (for example -\fB\-Dfoo="foo bar"\fR)\&. -.RE -.PP -\-d32 -.RS 4 -Runs the application in a 32\-bit environment\&. If a 32\-bit environment is not installed or is not supported, then an error will be reported\&. By default, the application is run in a 32\-bit environment unless a 64\-bit system is used\&. -.RE -.PP -\-d64 -.RS 4 -Runs the application in a 64\-bit environment\&. If a 64\-bit environment is not installed or is not supported, then an error will be reported\&. By default, the application is run in a 32\-bit environment unless a 64\-bit system is used\&. -.sp -Currently only the Java HotSpot Server VM supports 64\-bit operation, and the -\fB\-server\fR -option is implicit with the use of -\fB\-d64\fR\&. The -\fB\-client\fR -option is ignored with the use of -\fB\-d64\fR\&. This is subject to change in a future release\&. -.RE -.PP -\-disableassertions[:[\fIpackagename\fR]\&.\&.\&.|:\fIclassname\fR] +.RE + +.TP +-agentpath:\fIpathname\fR[=\fIoptions\fR] .br -\-da[:[\fIpackagename\fR]\&.\&.\&.|:\fIclassname\fR] -.RS 4 -Disables assertions\&. By default, assertions are disabled in all packages and classes\&. -.sp -With no arguments, -\fB\-disableassertions\fR -(\fB\-da\fR) disables assertions in all packages and classes\&. With the -\fIpackagename\fR -argument ending in -\fB\&.\&.\&.\fR, the switch disables assertions in the specified package and any subpackages\&. If the argument is simply -\fB\&.\&.\&.\fR, then the switch disables assertions in the unnamed package in the current working directory\&. With the -\fIclassname\fR -argument, the switch disables assertions in the specified class\&. -.sp -The -\fB\-disableassertions\fR -(\fB\-da\fR) option applies to all class loaders and to system classes (which do not have a class loader)\&. There is one exception to this rule: if the option is provided with no arguments, then it does not apply to system classes\&. This makes it easy to disable assertions in all classes except for system classes\&. The -\fB\-disablesystemassertions\fR -option enables you to disable assertions in all system classes\&. -.sp -To explicitly enable assertions in specific packages or classes, use the -\fB\-enableassertions\fR -(\fB\-ea\fR) option\&. Both options can be used at the same time\&. For example, to run the -\fBMyClass\fR -application with assertions enabled in package -\fBcom\&.wombat\&.fruitbat\fR -(and any subpackages) but disabled in class -\fBcom\&.wombat\&.fruitbat\&.Brickbat\fR, use the following command: -.sp -.if n \{\ -.RS 4 -.\} +Loads the native agent library specified by the absolute path name\&. This option is equivalent to \f3-agentlib\fR but uses the full path and file name of the library\&. +.TP +-client +.br +Selects the Java HotSpot Client VM\&. The 64-bit version of the Java SE Development Kit (JDK) currently ignores this option and instead uses the Server JVM\&. + +For default JVM selection, see Server-Class Machine Detection at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/server-class\&.html +.TP +-D\fIproperty\fR=\fIvalue\fR +.br +Sets a system property value\&. The \fIproperty\fR variable is a string with no spaces that represents the name of the property\&. The \fIvalue\fR variable is a string that represents the value of the property\&. If \fIvalue\fR is a string with spaces, then enclose it in quotation marks (for example \f3-Dfoo="foo bar"\fR)\&. +.TP +-d32 +.br +Runs the application in a 32-bit environment\&. If a 32-bit environment is not installed or is not supported, then an error will be reported\&. By default, the application is run in a 32-bit environment unless a 64-bit system is used\&. +.TP +-d64 +.br +Runs the application in a 64-bit environment\&. If a 64-bit environment is not installed or is not supported, then an error will be reported\&. By default, the application is run in a 32-bit environment unless a 64-bit system is used\&. + +Currently only the Java HotSpot Server VM supports 64-bit operation, and the \f3-server\fR option is implicit with the use of \f3-d64\fR\&. The \f3-client\fR option is ignored with the use of \f3-d64\fR\&. This is subject to change in a future release\&. +.TP .nf -\fBjava \-ea:com\&.wombat\&.fruitbat\&.\&.\&. \-da:com\&.wombat\&.fruitbat\&.Brickbat MyClass\fR - +-disableassertions[:[\fIpackagename\fR]\&.\&.\&.|:\fIclassname\fR], -da[:[\fIpackagename\fR]\&.\&.\&.|:\fIclassname\fR] +.br .fi -.if n \{\ -.RE -.\} -.RE -.PP -\-disablesystemassertions +Disables assertions\&. By default, assertions are disabled in all packages and classes\&. + +With no arguments, \f3-disableassertions\fR (\f3-da\fR) disables assertions in all packages and classes\&. With the \fIpackagename\fR argument ending in \f3\&.\&.\&.\fR, the switch disables assertions in the specified package and any subpackages\&. If the argument is simply \f3\&.\&.\&.\fR, then the switch disables assertions in the unnamed package in the current working directory\&. With the \fIclassname\fR argument\f3\fR, the switch disables assertions in the specified class\&. + +The \f3-disableassertions\fR (\f3-da\fR) option applies to all class loaders and to system classes (which do not have a class loader)\&. There is one exception to this rule: if the option is provided with no arguments, then it does not apply to system classes\&. This makes it easy to disable assertions in all classes except for system classes\&. The \f3-disablesystemassertions\fR option enables you to disable assertions in all system classes\&. + +To explicitly enable assertions in specific packages or classes, use the \f3-enableassertions\fR (\f3-ea\fR) option\&. Both options can be used at the same time\&. For example, to run the \f3MyClass\fR application with assertions enabled in package \f3com\&.wombat\&.fruitbat\fR (and any subpackages) but disabled in class \f3com\&.wombat\&.fruitbat\&.Brickbat\fR, use the following command: +.sp +.nf +\f3java \-ea:com\&.wombat\&.fruitbat\&.\&.\&. \-da:com\&.wombat\&.fruitbat\&.Brickbat MyClass\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-disablesystemassertions, -dsa .br -\-dsa -.RS 4 Disables assertions in all system classes\&. -.RE -.PP -\-enableassertions[:[\fIpackagename\fR]\&.\&.\&.|:\fIclassname\fR] -.br -\-ea[:[\fIpackagename\fR]\&.\&.\&.|:\fIclassname\fR] -.RS 4 -Enables assertions\&. By default, assertions are disabled in all packages and classes\&. -.sp -With no arguments, -\fB\-enableassertions\fR -(\fB\-ea\fR) enables assertions in all packages and classes\&. With the -\fIpackagename\fR -argument ending in -\fB\&.\&.\&.\fR, the switch enables assertions in the specified package and any subpackages\&. If the argument is simply -\fB\&.\&.\&.\fR, then the switch enables assertions in the unnamed package in the current working directory\&. With the -\fIclassname\fR -argument, the switch enables assertions in the specified class\&. -.sp -The -\fB\-enableassertions\fR -(\fB\-ea\fR) option applies to all class loaders and to system classes (which do not have a class loader)\&. There is one exception to this rule: if the option is provided with no arguments, then it does not apply to system classes\&. This makes it easy to enable assertions in all classes except for system classes\&. The -\fB\-enablesystemassertions\fR -option provides a separate switch to enable assertions in all system classes\&. -.sp -To explicitly disable assertions in specific packages or classes, use the -\fB\-disableassertions\fR -(\fB\-da\fR) option\&. If a single command contains multiple instances of these switches, then they are processed in order before loading any classes\&. For example, to run the -\fBMyClass\fR -application with assertions enabled only in package -\fBcom\&.wombat\&.fruitbat\fR -(and any subpackages) but disabled in class -\fBcom\&.wombat\&.fruitbat\&.Brickbat\fR, use the following command: -.sp -.if n \{\ -.RS 4 -.\} +.TP .nf -\fBjava \-ea:com\&.wombat\&.fruitbat\&.\&.\&. \-da:com\&.wombat\&.fruitbat\&.Brickbat MyClass\fR - +-enableassertions[:[\fIpackagename\fR]\&.\&.\&.|:\fIclassname\fR], -ea[:[\fIpackagename\fR]\&.\&.\&.|:\fIclassname\fR] +.br .fi -.if n \{\ -.RE -.\} -.RE -.PP -\-enablesystemassertions +Enables assertions\&. By default, assertions are disabled in all packages and classes\&. + +With no arguments, \f3-enableassertions\fR (\f3-ea\fR) enables assertions in all packages and classes\&. With the \fIpackagename\fR argument ending in \f3\&.\&.\&.\fR, the switch enables assertions in the specified package and any subpackages\&. If the argument is simply \f3\&.\&.\&.\fR, then the switch enables assertions in the unnamed package in the current working directory\&. With the \fIclassname\fR argument\f3\fR, the switch enables assertions in the specified class\&. + +The \f3-enableassertions\fR (\f3-ea\fR) option applies to all class loaders and to system classes (which do not have a class loader)\&. There is one exception to this rule: if the option is provided with no arguments, then it does not apply to system classes\&. This makes it easy to enable assertions in all classes except for system classes\&. The \f3-enablesystemassertions\fR option provides a separate switch to enable assertions in all system classes\&. + +To explicitly disable assertions in specific packages or classes, use the \f3-disableassertions\fR (\f3-da\fR) option\&. If a single command contains multiple instances of these switches, then they are processed in order before loading any classes\&. For example, to run the \f3MyClass\fR application with assertions enabled only in package \f3com\&.wombat\&.fruitbat\fR (and any subpackages) but disabled in class \f3com\&.wombat\&.fruitbat\&.Brickbat\fR, use the following command: +.sp +.nf +\f3java \-ea:com\&.wombat\&.fruitbat\&.\&.\&. \-da:com\&.wombat\&.fruitbat\&.Brickbat MyClass\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-enablesystemassertions, -esa .br -\-esa -.RS 4 Enables assertions in all system classes\&. -.RE -.PP -\-help -.br -\-? -.RS 4 -Displays usage information for the -\fBjava\fR -command without actually running the JVM\&. -.RE -.PP -\-jar \fIfilename\fR -.RS 4 -Executes a program encapsulated in a JAR file\&. The -\fIfilename\fR -argument is the name of a JAR file with a manifest that contains a line in the form -\fBMain\-Class:\fR\fIclassname\fR -that defines the class with the -\fBpublic static void main(String[] args)\fR -method that serves as your application\*(Aqs starting point\&. -.sp -When you use the -\fB\-jar\fR -option, the specified JAR file is the source of all user classes, and other class path settings are ignored\&. -.sp +.TP +-help, -? +.br +Displays usage information for the \f3java\fR command without actually running the JVM\&. +.TP +-jar \fIfilename\fR +.br +Executes a program encapsulated in a JAR file\&. The \fIfilename\fR argument is the name of a JAR file with a manifest that contains a line in the form \f3Main-Class:\fR\fIclassname\fR that defines the class with the \f3public static void main(String[] args)\fR method that serves as your application\&'s starting point\&. + +When you use the \f3-jar\fR option, the specified JAR file is the source of all user classes, and other class path settings are ignored\&. + For more information about JAR files, see the following resources: -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.RS +.TP 0.2i +\(bu jar(1) -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu The Java Archive (JAR) Files guide at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/jar/index\&.html -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Lesson: Packaging Programs in JAR Files at - -http://docs\&.oracle\&.com/javase/tutorial/deployment/jar/index\&.html -.RE -.RE -.PP -\-javaagent:\fIjarpath\fR[=\fIoptions\fR] -.RS 4 -Loads the specified Java programming language agent\&. For more information about instrumenting Java applications, see the -\fBjava\&.lang\&.instrument\fR -package description in the Java API documentation at http://docs\&.oracle\&.com/javase/8/docs/api/java/lang/instrument/package\-summary\&.html -.RE -.PP -\-jre\-restrict\-search -.RS 4 -Includes user\-private JREs in the version search\&. -.RE -.PP -\-no\-jre\-restrict\-search -.RS 4 -Excludes user\-private JREs from the version search\&. -.RE -.PP -\-server -.RS 4 -Selects the Java HotSpot Server VM\&. The 64\-bit version of the JDK supports only the Server VM, so in that case the option is implicit\&. -.sp -For default JVM selection, see Server\-Class Machine Detection at - -http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/server\-class\&.html -.RE -.PP -\-showversion -.RS 4 -Displays version information and continues execution of the application\&. This option is equivalent to the -\fB\-version\fR -option except that the latter instructs the JVM to exit after displaying version information\&. -.RE -.PP -\-splash:\fIimgname\fR -.RS 4 -Shows the splash screen with the image specified by -\fIimgname\fR\&. For example, to show the -\fBsplash\&.gif\fR -file from the -\fBimages\fR -directory when starting your application, use the following option: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-splash:images/splash\&.gif\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-verbose:class -.RS 4 +.TP 0.2i +\(bu +Lesson: Packaging Programs in JAR Files at http://docs\&.oracle\&.com/javase/tutorial/deployment/jar/index\&.html +.RE + +.TP +-javaagent:\fIjarpath\fR[=\fIoptions\fR] +.br +Loads the specified Java programming language agent\&. For more information about instrumenting Java applications, see the \f3java\&.lang\&.instrument\fR package description in the Java API documentation at http://docs\&.oracle\&.com/javase/8/docs/api/java/lang/instrument/package-summary\&.html +.TP +-jre-restrict-search +.br +Includes user-private JREs in the version search\&. +.TP +-no-jre-restrict-search +.br +Excludes user-private JREs from the version search\&. +.TP +-server +.br +Selects the Java HotSpot Server VM\&. The 64-bit version of the JDK supports only the Server VM, so in that case the option is implicit\&. + +For default JVM selection, see Server-Class Machine Detection at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/server-class\&.html +.TP +-showversion +.br +Displays version information and continues execution of the application\&. This option is equivalent to the \f3-version\fR option except that the latter instructs the JVM to exit after displaying version information\&. +.TP +-splash:\fIimgname\fR +.br +Shows the splash screen with the image specified by \fIimgname\fR\&. For example, to show the \f3splash\&.gif\fR file from the \f3images\fR directory when starting your application, use the following option: +.sp +.nf +\f3\-splash:images/splash\&.gif\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-verbose:class +.br Displays information about each loaded class\&. -.RE -.PP -\-verbose:gc -.RS 4 +.TP +-verbose:gc +.br Displays information about each garbage collection (GC) event\&. -.RE -.PP -\-verbose:jni -.RS 4 +.TP +-verbose:jni +.br Displays information about the use of native methods and other Java Native Interface (JNI) activity\&. -.RE -.PP -\-version -.RS 4 -Displays version information and then exits\&. This option is equivalent to the -\fB\-showversion\fR -option except that the latter does not instruct the JVM to exit after displaying version information\&. -.RE -.PP -\-version:\fIrelease\fR -.RS 4 -Specifies the release version to be used for running the application\&. If the version of the -\fBjava\fR -command called does not meet this specification and an appropriate implementation is found on the system, then the appropriate implementation will be used\&. -.sp -The -\fIrelease\fR -argument specifies either the exact version string, or a list of version strings and ranges separated by spaces\&. A -\fIversion string\fR -is the developer designation of the version number in the following form: -\fB1\&.\fR\fIx\fR\fB\&.0_\fR\fIu\fR -(where -\fIx\fR -is the major version number, and -\fIu\fR -is the update version number)\&. A -\fIversion range\fR -is made up of a version string followed by a plus sign (\fB+\fR) to designate this version or later, or a part of a version string followed by an asterisk (\fB*\fR) to designate any version string with a matching prefix\&. Version strings and ranges can be combined using a space for a logical -\fIOR\fR -combination, or an ampersand (\fB&\fR) for a logical -\fIAND\fR -combination of two version strings/ranges\&. For example, if running the class or JAR file requires either JRE 6u13 (1\&.6\&.0_13), or any JRE 6 starting from 6u10 (1\&.6\&.0_10), specify the following: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-version:"1\&.6\&.0_13 1\&.6* & 1\&.6\&.0_10+"\fR - -.fi -.if n \{\ -.RE -.\} -Quotation marks are necessary only if there are spaces in the -\fIrelease\fR -parameter\&. -.sp +.TP +-version +.br +Displays version information and then exits\&. This option is equivalent to the \f3-showversion\fR option except that the latter does not instruct the JVM to exit after displaying version information\&. +.TP +-version:\fIrelease\fR +.br +Specifies the release version to be used for running the application\&. If the version of the \f3java\fR command called does not meet this specification and an appropriate implementation is found on the system, then the appropriate implementation will be used\&. + +The \fIrelease\fR argument specifies either the exact version string, or a list of version strings and ranges separated by spaces\&. A \fIversion string\fR is the developer designation of the version number in the following form: \f31\&.\fR\fIx\fR\f3\&.0_\fR\fIu\fR (where \fIx\fR is the major version number, and \fIu\fR is the update version number)\&. A \fIversion range\fR is made up of a version string followed by a plus sign (\f3+\fR) to designate this version or later, or a part of a version string followed by an asterisk (\f3*\fR) to designate any version string with a matching prefix\&. Version strings and ranges can be combined using a space for a logical \fIOR\fR combination, or an ampersand (\f3&\fR) for a logical \fIAND\fR combination of two version strings/ranges\&. For example, if running the class or JAR file requires either JRE 6u13 (1\&.6\&.0_13), or any JRE 6 starting from 6u10 (1\&.6\&.0_10), specify the following: +.sp +.nf +\f3\-version:"1\&.6\&.0_13 1\&.6* & 1\&.6\&.0_10+"\fP +.fi +.nf +\f3\fP +.fi +.sp + + +Quotation marks are necessary only if there are spaces in the \fIrelease\fR parameter\&. + For JAR files, the preference is to specify version requirements in the JAR file manifest rather than on the command line\&. -.RE -.SS "Non\-Standard Options" -.PP +.SS NON-STANDARD\ OPTIONS These options are general purpose options that are specific to the Java HotSpot Virtual Machine\&. -.PP -\-X -.RS 4 -Displays help for all available -\fB\-X\fR -options\&. -.RE -.PP -\-Xbatch -.RS 4 -Disables background compilation\&. By default, the JVM compiles the method as a background task, running the method in interpreter mode until the background compilation is finished\&. The -\fB\-Xbatch\fR -flag disables background compilation so that compilation of all methods proceeds as a foreground task until completed\&. -.sp -This option is equivalent to -\fB\-XX:\-BackgroundCompilation\fR\&. -.RE -.PP -\-Xbootclasspath:\fIpath\fR -.RS 4 +.TP +-X +.br +Displays help for all available \f3-X\fR options\&. +.TP +-Xbatch +.br +Disables background compilation\&. By default, the JVM compiles the method as a background task, running the method in interpreter mode until the background compilation is finished\&. The \f3-Xbatch\fR flag disables background compilation so that compilation of all methods proceeds as a foreground task until completed\&. + +This option is equivalent to \f3-XX:-BackgroundCompilation\fR\&. +.TP +-Xbootclasspath:\fIpath\fR +.br Specifies a list of directories, JAR files, and ZIP archives separated by colons (:) to search for boot class files\&. These are used in place of the boot class files included in the JDK\&. -.sp -Do not deploy applications that use this option to override a class in -\fBrt\&.jar\fR, because this violates the JRE binary code license\&. -.RE -.PP -\-Xbootclasspath/a:\fIpath\fR -.RS 4 + +\fI\fRDo not deploy applications that use this option to override a class in \f3rt\&.jar\fR, because this violates the JRE binary code license\&. +.TP +-Xbootclasspath/a:\fIpath\fR +.br Specifies a list of directories, JAR files, and ZIP archives separated by colons (:) to append to the end of the default bootstrap class path\&. -.sp -Do not deploy applications that use this option to override a class in -\fBrt\&.jar\fR, because this violates the JRE binary code license\&. -.RE -.PP -\-Xbootclasspath/p:\fIpath\fR -.RS 4 + +Do not deploy applications that use this option to override a class in \f3rt\&.jar\fR, because this violates the JRE binary code license\&. +.TP +-Xbootclasspath/p:\fIpath\fR +.br Specifies a list of directories, JAR files, and ZIP archives separated by colons (:) to prepend to the front of the default bootstrap class path\&. -.sp -Do not deploy applications that use this option to override a class in -\fBrt\&.jar\fR, because this violates the JRE binary code license\&. -.RE -.PP -\-Xcheck:jni -.RS 4 + +Do not deploy applications that use this option to override a class in \f3rt\&.jar\fR, because this violates the JRE binary code license\&. +.TP +-Xcheck:jni +.br Performs additional checks for Java Native Interface (JNI) functions\&. Specifically, it validates the parameters passed to the JNI function and the runtime environment data before processing the JNI request\&. Any invalid data encountered indicates a problem in the native code, and the JVM will terminate with an irrecoverable error in such cases\&. Expect a performance degradation when this option is used\&. -.RE -.PP -\-Xcomp -.RS 4 -Forces compilation of methods on first invocation\&. By default, the Client VM (\fB\-client\fR) performs 1,000 interpreted method invocations and the Server VM (\fB\-server\fR) performs 10,000 interpreted method invocations to gather information for efficient compilation\&. Specifying the -\fB\-Xcomp\fR -option disables interpreted method invocations to increase compilation performance at the expense of efficiency\&. -.sp -You can also change the number of interpreted method invocations before compilation using the -\fB\-XX:CompileThreshold\fR -option\&. -.RE -.PP -\-Xdebug -.RS 4 +.TP +-Xcomp +.br +Forces compilation of methods on first invocation\&. By default, the Client VM (\f3-client\fR) performs 1,000 interpreted method invocations and the Server VM (\f3-server\fR) performs 10,000 interpreted method invocations to gather information for efficient compilation\&. Specifying the \f3-Xcomp\fR option disables interpreted method invocations to increase compilation performance at the expense of efficiency\&. + +You can also change the number of interpreted method invocations before compilation using the \f3-XX:CompileThreshold\fR option\&. +.TP +-Xdebug +.br Does nothing\&. Provided for backward compatibility\&. -.RE -.PP -\-Xdiag -.RS 4 +.TP +-Xdiag +.br Shows additional diagnostic messages\&. -.RE -.PP -\-Xfuture -.RS 4 -Enables strict class\-file format checks that enforce close conformance to the class\-file format specification\&. Developers are encouraged to use this flag when developing new code because the stricter checks will become the default in future releases\&. -.RE -.PP -\-Xint -.RS 4 -Runs the application in interpreted\-only mode\&. Compilation to native code is disabled, and all bytecode is executed by the interpreter\&. The performance benefits offered by the just in time (JIT) compiler are not present in this mode\&. -.RE -.PP -\-Xinternalversion -.RS 4 -Displays more detailed JVM version information than the -\fB\-version\fR -option, and then exits\&. -.RE -.PP -\-Xloggc:\fIfilename\fR -.RS 4 -Sets the file to which verbose GC events information should be redirected for logging\&. The information written to this file is similar to the output of -\fB\-verbose:gc\fR -with the time elapsed since the first GC event preceding each logged event\&. The -\fB\-Xloggc\fR -option overrides -\fB\-verbose:gc\fR -if both are given with the same -\fBjava\fR -command\&. -.sp +.TP +-Xfuture +.br +Enables strict class-file format checks that enforce close conformance to the class-file format specification\&. Developers are encouraged to use this flag when developing new code because the stricter checks will become the default in future releases\&. +.TP +-Xint +.br +Runs the application in interpreted-only mode\&. Compilation to native code is disabled, and all bytecode is executed by the interpreter\&. The performance benefits offered by the just in time (JIT) compiler are not present in this mode\&. +.TP +-Xinternalversion +.br +Displays more detailed JVM version information than the \f3-version\fR option, and then exits\&. +.TP +-Xloggc:\fIfilename\fR +.br +Sets the file to which verbose GC events information should be redirected for logging\&. The information written to this file is similar to the output of \f3-verbose:gc\fR with the time elapsed since the first GC event preceding each logged event\&. The \f3-Xloggc\fR option overrides \f3-verbose:gc\fR if both are given with the same \f3java\fR command\&. + Example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-Xloggc:garbage\-collection\&.log\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-Xmaxjitcodesize=\fIsize\fR -.RS 4 -Specifies the maximum code cache size (in bytes) for JIT\-compiled code\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. By default, the value is set to 48 MB: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-Xmaxjitcodesize=48m\fR - -.fi -.if n \{\ -.RE -.\} -This option is equivalent to -\fB\-XX:ReservedCodeCacheSize\fR\&. -.RE -.PP -\-Xmixed -.RS 4 +.sp +.nf +\f3\-Xloggc:garbage\-collection\&.log\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-Xmaxjitcodesize=\fIsize\fR +.br +Specifies the maximum code cache size (in bytes) for JIT-compiled code\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. By default, the value is set to 48 MB: +.sp +.nf +\f3\-Xmaxjitcodesize=48m\fP +.fi +.nf +\f3\fP +.fi +.sp + + +This option is equivalent to \f3-XX:ReservedCodeCacheSize\fR\&. +.TP +-Xmixed +.br Executes all bytecode by the interpreter except for hot methods, which are compiled to native code\&. -.RE -.PP -\-Xmn\fIsize\fR -.RS 4 -Sets the initial and maximum size (in bytes) of the heap for the young generation (nursery)\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. -.sp +.TP +-Xmn\fIsize\fR +.br +Sets the initial and maximum size (in bytes) of the heap for the young generation (nursery)\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. + The young generation region of the heap is used for new objects\&. GC is performed in this region more often than in other regions\&. If the size for the young generation is too small, then a lot of minor garbage collections will be performed\&. If the size is too large, then only full garbage collections will be performed, which can take a long time to complete\&. Oracle recommends that you keep the size for the young generation between a half and a quarter of the overall heap size\&. -.sp + The following examples show how to set the initial and maximum size of young generation to 256 MB using various units: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-Xmn256m\fR -\fB\-Xmn262144k\fR -\fB\-Xmn268435456\fR - -.fi -.if n \{\ -.RE -.\} -Instead of the -\fB\-Xmn\fR -option to set both the initial and maximum size of the heap for the young generation, you can use -\fB\-XX:NewSize\fR -to set the initial size and -\fB\-XX:MaxNewSize\fR -to set the maximum size\&. -.RE -.PP -\-Xms\fIsize\fR -.RS 4 -Sets the initial size (in bytes) of the heap\&. This value must be a multiple of 1024 and greater than 1 MB\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. -.sp +.sp +.nf +\f3\-Xmn256m\fP +.fi +.nf +\f3\-Xmn262144k\fP +.fi +.nf +\f3\-Xmn268435456\fP +.fi +.nf +\f3\fP +.fi +.sp + + +Instead of the \f3-Xmn\fR option to set both the initial and maximum size of the heap for the young generation, you can use \f3-XX:NewSize\fR to set the initial size and \f3-XX:MaxNewSize\fR to set the maximum size\&. +.TP +-Xms\fIsize\fR +.br +Sets the initial size (in bytes) of the heap\&. This value must be a multiple of 1024 and greater than 1 MB\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. + The following examples show how to set the size of allocated memory to 6 MB using various units: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-Xms6291456\fR -\fB\-Xms6144k\fR -\fB\-Xms6m\fR - -.fi -.if n \{\ -.RE -.\} -If you do not set this option, then the initial size will be set as the sum of the sizes allocated for the old generation and the young generation\&. The initial size of the heap for the young generation can be set using the -\fB\-Xmn\fR -option or the -\fB\-XX:NewSize\fR -option\&. -.RE -.PP -\-Xmx\fIsize\fR -.RS 4 -Specifies the maximum size (in bytes) of the memory allocation pool in bytes\&. This value must be a multiple of 1024 and greater than 2 MB\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. The default value is chosen at runtime based on system configuration\&. For server deployments, -\fB\-Xms\fR -and -\fB\-Xmx\fR -are often set to the same value\&. For more information, see Garbage Collector Ergonomics at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/gc\-ergonomics\&.html -.sp +.sp +.nf +\f3\-Xms6291456\fP +.fi +.nf +\f3\-Xms6144k\fP +.fi +.nf +\f3\-Xms6m\fP +.fi +.nf +\f3\fP +.fi +.sp + + +If you do not set this option, then the initial size will be set as the sum of the sizes allocated for the old generation and the young generation\&. The initial size of the heap for the young generation can be set using the \f3-Xmn\fR option or the \f3-XX:NewSize\fR option\&. +.TP +-Xmx\fIsize\fR +.br +Specifies the maximum size (in bytes) of the memory allocation pool in bytes\&. This value must be a multiple of 1024 and greater than 2 MB\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. The default value is chosen at runtime based on system configuration\&. For server deployments, \f3-Xms\fR and \f3-Xmx\fR are often set to the same value\&. See the section "Ergonomics" in \fIJava SE HotSpot Virtual Machine Garbage Collection Tuning Guide\fR at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/gctuning/index\&.html\&. + The following examples show how to set the maximum allowed size of allocated memory to 80 MB using various units: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-Xmx83886080\fR -\fB\-Xmx81920k\fR -\fB\-Xmx80m\fR - -.fi -.if n \{\ -.RE -.\} -The -\fB\-Xmx\fR -option is equivalent to -\fB\-XX:MaxHeapSize\fR\&. -.RE -.PP -\-Xnoclassgc -.RS 4 +.sp +.nf +\f3\-Xmx83886080\fP +.fi +.nf +\f3\-Xmx81920k\fP +.fi +.nf +\f3\-Xmx80m\fP +.fi +.nf +\f3\fP +.fi +.sp + + +The \f3-Xmx\fR option is equivalent to \f3-XX:MaxHeapSize\fR\&. +.TP +-Xnoclassgc +.br Disables garbage collection (GC) of classes\&. This can save some GC time, which shortens interruptions during the application run\&. -.sp -When you specify -\fB\-Xnoclassgc\fR -at startup, the class objects in the application will be left untouched during GC and will always be considered live\&. This can result in more memory being permanently occupied which, if not used carefully, will throw an out of memory exception\&. -.RE -.PP -\-Xprof -.RS 4 + +When you specify \f3-Xnoclassgc\fR at startup, the class objects in the application will be left untouched during GC and will always be considered live\&. This can result in more memory being permanently occupied which, if not used carefully, will throw an out of memory exception\&. +.TP +-Xprof +.br Profiles the running program and sends profiling data to standard output\&. This option is provided as a utility that is useful in program development and is not intended to be used in production systems\&. -.RE -.PP -\-Xrs -.RS 4 +.TP +-Xrs +.br Reduces the use of operating system signals by the JVM\&. -.sp + Shutdown hooks enable orderly shutdown of a Java application by running user cleanup code (such as closing database connections) at shutdown, even if the JVM terminates abruptly\&. -.sp -The JVM catches signals to implement shutdown hooks for unexpected termination\&. The JVM uses -\fBSIGHUP\fR, -\fBSIGINT\fR, and -\fBSIGTERM\fR -to initiate the running of shutdown hooks\&. -.sp -The JVM uses a similar mechanism to implement the feature of dumping thread stacks for debugging purposes\&. The JVM uses -\fBSIGQUIT\fR -to perform thread dumps\&. -.sp -Applications embedding the JVM frequently need to trap signals such as -\fBSIGINT\fR -or -\fBSIGTERM\fR, which can lead to interference with the JVM signal handlers\&. The -\fB\-Xrs\fR -option is available to address this issue\&. When -\fB\-Xrs\fR -is used, the signal masks for -\fBSIGINT\fR, -\fBSIGTERM\fR, -\fBSIGHUP\fR, and -\fBSIGQUIT\fR -are not changed by the JVM, and signal handlers for these signals are not installed\&. -.sp -There are two consequences of specifying -\fB\-Xrs\fR: -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -\fBSIGQUIT\fR -thread dumps are not available\&. -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -User code is responsible for causing shutdown hooks to run, for example, by calling -\fBSystem\&.exit()\fR -when the JVM is to be terminated\&. -.RE -.RE -.PP -\-Xshare:\fImode\fR -.RS 4 -Sets the class data sharing mode\&. Possible -\fImode\fR -arguments for this option include the following: -.PP + +The JVM catches signals to implement shutdown hooks for unexpected termination\&. The JVM uses \f3SIGHUP\fR, \f3SIGINT\fR, and \f3SIGTERM\fR to initiate the running of shutdown hooks\&. + +The JVM uses a similar mechanism to implement the feature of dumping thread stacks for debugging purposes\&. The JVM uses \f3SIGQUIT\fR to perform thread dumps\&. + +Applications embedding the JVM frequently need to trap signals such as \f3SIGINT\fR or \f3SIGTERM\fR, which can lead to interference with the JVM signal handlers\&. The \f3-Xrs\fR option is available to address this issue\&. When \f3-Xrs\fR is used, the signal masks for \f3SIGINT\fR, \f3SIGTERM\fR, \f3SIGHUP\fR, and \f3SIGQUIT\fR are not changed by the JVM, and signal handlers for these signals are not installed\&. + +There are two consequences of specifying \f3-Xrs\fR: +.RS +.TP 0.2i +\(bu +\f3SIGQUIT\fR thread dumps are not available\&. +.TP 0.2i +\(bu +User code is responsible for causing shutdown hooks to run, for example, by calling \f3System\&.exit()\fR when the JVM is to be terminated\&. +.RE + +.TP +-Xshare:\fImode\fR +.br +Sets the class data sharing mode\&. Possible \fImode\fR arguments for this option include the following: +.RS +.TP auto -.RS 4 -Use shared class data if possible\&. This is the default value for Java HotSpot 32\-Bit Client VM\&. -.RE -.PP +Use shared class data if possible\&. This is the default value for Java HotSpot 32-Bit Client VM\&. +.TP on -.RS 4 Require the use of class data sharing\&. Print an error message and exit if class data sharing cannot be used\&. -.RE -.PP +.TP off -.RS 4 -Do not use shared class data\&. This is the default value for Java HotSpot 32\-Bit Server VM, Java HotSpot 64\-Bit Client VM, and Java HotSpot 64\-Bit Server VM\&. -.RE -.PP +Do not use shared class data\&. This is the default value for Java HotSpot 32-Bit Server VM, Java HotSpot 64-Bit Client VM, and Java HotSpot 64-Bit Server VM\&. +.TP dump -.RS 4 Manually generate the class data sharing archive\&. -.RE -.RE -.PP -\-XshowSettings:\fIcategory\fR -.RS 4 -Shows settings and continues\&. Possible -\fIcategory\fR -arguments for this option include the following: -.PP +.RE + +.TP +-XshowSettings:\fIcategory\fR +.br +Shows settings and continues\&. Possible \fIcategory\fR arguments for this option include the following: +.RS +.TP all -.RS 4 Shows all categories of settings\&. This is the default value\&. -.RE -.PP +.TP locale -.RS 4 Shows settings related to locale\&. -.RE -.PP +.TP properties -.RS 4 Shows settings related to system properties\&. -.RE -.PP +.TP vm -.RS 4 Shows the settings of the JVM\&. -.RE -.RE -.PP -\-Xss\fIsize\fR -.RS 4 -Sets the thread stack size (in bytes)\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate KB, -\fBm\fR -or -\fBM\fR -to indicate MB, -\fBg\fR -or -\fBG\fR -to indicate GB\&. The default value depends on the platform: -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Linux/ARM (32\-bit): 320 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Linux/i386 (32\-bit): 320 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Linux/x64 (64\-bit): 1024 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -OS X (64\-bit): 1024 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Oracle Solaris/i386 (32\-bit): 320 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Oracle Solaris/x64 (64\-bit): 1024 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.RE + +.TP +-Xss\fIsize\fR +.br +Sets the thread stack size (in bytes)\&. Append the letter \f3k\fR or \f3K\fR to indicate KB, \f3m\fR or \f3M\fR to indicate MB, \f3g\fR or \f3G\fR to indicate GB\&. The default value depends on the platform: +.RS +.TP 0.2i +\(bu +Linux/ARM (32-bit): 320 KB +.TP 0.2i +\(bu +Linux/i386 (32-bit): 320 KB +.TP 0.2i +\(bu +Linux/x64 (64-bit): 1024 KB +.TP 0.2i +\(bu +OS X (64-bit): 1024 KB +.TP 0.2i +\(bu +Oracle Solaris/i386 (32-bit): 320 KB +.TP 0.2i +\(bu +Oracle Solaris/x64 (64-bit): 1024 KB +.TP 0.2i +\(bu Windows: depends on virtual memory -.RE -.sp +.RE + + The following examples set the thread stack size to 1024 KB in different units: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-Xss1m\fR -\fB\-Xss1024k\fR -\fB\-Xss1048576\fR - -.fi -.if n \{\ -.RE -.\} -This option is equivalent to -\fB\-XX:ThreadStackSize\fR\&. -.RE -.PP -\-Xusealtsigs -.RS 4 -Use alternative signals instead of -\fBSIGUSR1\fR -and -\fBSIGUSR2\fR -for JVM internal signals\&. This option is equivalent to -\fB\-XX:+UseAltSigs\fR\&. -.RE -.PP -\-Xverify:\fImode\fR -.RS 4 -Sets the mode of the bytecode verifier\&. Bytecode verification helps to troubleshoot some problems, but it also adds overhead to the running application\&. Possible -\fImode\fR -arguments for this option include the following: -.PP +.sp +.nf +\f3\-Xss1m\fP +.fi +.nf +\f3\-Xss1024k\fP +.fi +.nf +\f3\-Xss1048576\fP +.fi +.nf +\f3\fP +.fi +.sp + + +This option is equivalent to \f3-XX:ThreadStackSize\fR\&. +.TP +-Xusealtsigs +.br +Use alternative signals instead of \f3SIGUSR1\fR and \f3SIGUSR2\fR for JVM internal signals\&. This option is equivalent to \f3-XX:+UseAltSigs\fR\&. +.TP +-Xverify:\fImode\fR +.br +Sets the mode of the bytecode verifier\&. Bytecode verification helps to troubleshoot some problems, but it also adds overhead to the running application\&. Possible \fImode\fR arguments for this option include the following: +.RS +.TP none -.RS 4 Do not verify the bytecode\&. This reduces startup time and also reduces the protection provided by Java\&. -.RE -.PP +.TP remote -.RS 4 -Verify only those classes that are loaded remotely over the network\&. This is the default behavior if you do not specify the -\fB\-Xverify\fR -option\&. -.RE -.PP +Verify those classes that are not loaded by the bootstrap class loader\&. This is the default behavior if you do not specify the \f3-Xverify\fR option\&. +.TP all -.RS 4 Verify all classes\&. -.RE -.RE -.SS "Advanced Runtime Options" -.PP +.RE + +.SS ADVANCED\ RUNTIME\ OPTIONS These options control the runtime behavior of the Java HotSpot VM\&. -.PP -\-XX:+DisableAttachMechanism -.RS 4 -Enables the option that disables the mechanism that lets tools attach to the JVM\&. By default, this option is disabled, meaning that the attach mechanism is enabled and you can use tools such as -\fBjcmd\fR, -\fBjstack\fR, -\fBjmap\fR, and -\fBjinfo\fR\&. -.RE -.PP -\-XX:ErrorFile=\fIfilename\fR -.RS 4 -Specifies the path and file name to which error data is written when an irrecoverable error occurs\&. By default, this file is created in the current working directory and named -\fBhs_err_pid\fR\fIpid\fR\fB\&.log\fR -where -\fIpid\fR -is the identifier of the process that caused the error\&. The following example shows how to set the default log file (note that the identifier of the process is specified as -\fB%p\fR): -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:ErrorFile=\&./hs_err_pid%p\&.log\fR - -.fi -.if n \{\ -.RE -.\} -The following example shows how to set the error log to -\fB/var/log/java/java_error\&.log\fR: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:ErrorFile=/var/log/java/java_error\&.log\fR - -.fi -.if n \{\ -.RE -.\} -If the file cannot be created in the specified directory (due to insufficient space, permission problem, or another issue), then the file is created in the temporary directory for the operating system\&. The temporary directory is -\fB/tmp\fR\&. -.RE -.PP -\-XX:+FailOverToOldVerifier -.RS 4 +.TP +-XX:+DisableAttachMechanism +.br +Enables the option that disables the mechanism that lets tools attach to the JVM\&. By default, this option is disabled, meaning that the attach mechanism is enabled and you can use tools such as \f3jcmd\fR, \f3jstack\fR, \f3jmap\fR, and \f3jinfo\fR\&. +.TP +-XX:ErrorFile=\fIfilename\fR +.br +Specifies the path and file name to which error data is written when an irrecoverable error occurs\&. By default, this file is created in the current working directory and named \f3hs_err_pid\fR\fIpid\fR\f3\&.log\fR where \fIpid\fR is the identifier of the process that caused the error\&. The following example shows how to set the default log file (note that the identifier of the process is specified as \f3%p\fR): +.sp +.nf +\f3\-XX:ErrorFile=\&./hs_err_pid%p\&.log\fP +.fi +.nf +\f3\fP +.fi +.sp + + +The following example shows how to set the error log to \f3/var/log/java/java_error\&.log\fR: +.sp +.nf +\f3\-XX:ErrorFile=/var/log/java/java_error\&.log\fP +.fi +.nf +\f3\fP +.fi +.sp + + +If the file cannot be created in the specified directory (due to insufficient space, permission problem, or another issue), then the file is created in the temporary directory for the operating system\&. The temporary directory is \f3/tmp\fR\&. +.TP +-XX:+FailOverToOldVerifier +.br Enables automatic failover to the old verifier when the new type checker fails\&. By default, this option is disabled and it is ignored (that is, treated as disabled) for classes with a recent bytecode version\&. You can enable it for classes with older versions of the bytecode\&. -.RE -.PP -\-XX:LargePageSizeInBytes=\fIsize\fR -.RS 4 -Sets the maximum size (in bytes) for large pages used for Java heap\&. The -\fIsize\fR -argument must be a power of 2 (2, 4, 8, 16, \&.\&.\&.)\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. By default, the size is set to 0, meaning that the JVM chooses the size for large pages automatically\&. -.sp +.TP +-XX:LargePageSizeInBytes=\fIsize\fR +.br +On Solaris, sets the maximum size (in bytes) for large pages used for Java heap\&. The \fIsize\fR argument must be a power of 2 (2, 4, 8, 16, \&.\&.\&.)\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. By default, the size is set to 0, meaning that the JVM chooses the size for large pages automatically\&. + The following example illustrates how to set the large page size to 4 megabytes (MB): -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:LargePageSizeInBytes=4m\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:MaxDirectMemorySize=\fIsize\fR -.RS 4 -Sets the maximum total size (in bytes) of the New I/O (the -\fBjava\&.nio\fR -package) direct\-buffer allocations\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. By default, the size is set to 0, meaning that the JVM chooses the size for NIO direct\-buffer allocations automatically\&. -.sp +.sp +.nf +\f3\-XX:LargePageSizeInBytes=4m\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:MaxDirectMemorySize=\fIsize\fR +.br +Sets the maximum total size (in bytes) of the New I/O (the \f3java\&.nio\fR package) direct-buffer allocations\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. By default, the size is set to 0, meaning that the JVM chooses the size for NIO direct-buffer allocations automatically\&. + The following examples illustrate how to set the NIO size to 1024 KB in different units: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MaxDirectMemorySize=1m\fR -\fB\-XX:MaxDirectMemorySize=1024k\fR -\fB\-XX:MaxDirectMemorySize=1048576\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:NativeMemoryTracking=\fImode\fR -.RS 4 -Specifies the mode for tracking JVM native memory usage\&. Possible -\fImode\fR -arguments for this option include the following: -.PP +.sp +.nf +\f3\-XX:MaxDirectMemorySize=1m\fP +.fi +.nf +\f3\-XX:MaxDirectMemorySize=1024k\fP +.fi +.nf +\f3\-XX:MaxDirectMemorySize=1048576\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:NativeMemoryTracking=\fImode\fR +.br +Specifies the mode for tracking JVM native memory usage\&. Possible \fImode\fR arguments for this option include the following: +.RS +.TP off -.RS 4 -Do not track JVM native memory usage\&. This is the default behavior if you do not specify the -\fB\-XX:NativeMemoryTracking\fR -option\&. -.RE -.PP +Do not track JVM native memory usage\&. This is the default behavior if you do not specify the \f3-XX:NativeMemoryTracking\fR option\&. +.TP summary -.RS 4 Only track memory usage by JVM subsystems, such as Java heap, class, code, and thread\&. -.RE -.PP +.TP detail -.RS 4 -In addition to tracking memory usage by JVM subsystems, track memory usage by individual -\fBCallSite\fR, individual virtual memory region and its committed regions\&. -.RE -.RE -.PP -\-XX:OnError=\fIstring\fR -.RS 4 -Sets a custom command or a series of semicolon\-separated commands to run when an irrecoverable error occurs\&. If the string contains spaces, then it must be enclosed in quotation marks\&. -.sp -The following example shows how the -\fB\-XX:OnError\fR -option can be used to run the -\fBgcore\fR -command to create the core image, and the debugger is started to attach to the process in case of an irrecoverable error (the -\fB%p\fR -designates the current process): -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:OnError="gcore %p;dbx \- %p"\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:OnOutOfMemoryError=\fIstring\fR -.RS 4 -Sets a custom command or a series of semicolon\-separated commands to run when an -\fBOutOfMemoryError\fR -exception is first thrown\&. If the string contains spaces, then it must be enclosed in quotation marks\&. For an example of a command string, see the description of the -\fB\-XX:OnError\fR -option\&. -.RE -.PP -\-XX:+PrintCommandLineFlags -.RS 4 -Enables printing of ergonomically selected JVM flags that appeared on the command line\&. It can be useful to know the ergonomic values set by the JVM, such as the heap space size and the selected garbage collector\&. By default, this option is disabled and flags are not printed\&. -.RE -.PP -\-XX:+PrintNMTStatistics -.RS 4 -Enables printing of collected native memory tracking data at JVM exit when native memory tracking is enabled (see -\fB\-XX:NativeMemoryTracking\fR)\&. By default, this option is disabled and native memory tracking data is not printed\&. -.RE -.PP -\-XX:+RelaxAccessControlCheck -.RS 4 +In addition to tracking memory usage by JVM subsystems, track memory usage by individual \f3CallSite\fR, individual virtual memory region and its committed regions\&. +.RE + +.TP +-XX:ObjectAlignmentInBytes=\fIalignment\fR +.br +Sets the memory alignment of Java objects (in bytes)\&. By default, the value is set to 8 bytes\&. The specified value should be a power of two, and must be within the range of 8 and 256 (inclusive)\&. This option makes it possible to use compressed pointers with large Java heap sizes\&. + +The heap size limit in bytes is calculated as: + +\f34GB * ObjectAlignmentInBytes\fR + +Note: As the alignment value increases, the unused space between objects will also increase\&. As a result, you may not realize any benefits from using compressed pointers with large Java heap sizes\&. +.TP +-XX:OnError=\fIstring\fR +.br +Sets a custom command or a series of semicolon-separated commands to run when an irrecoverable error occurs\&. If the string contains spaces, then it must be enclosed in quotation marks\&. + +\fI\fRThe following example shows how the \f3-XX:OnError\fR option can be used to run the \f3gcore\fR command to create the core image, and the debugger is started to attach to the process in case of an irrecoverable error (the \f3%p\fR designates the current process): +.sp +.nf +\f3\-XX:OnError="gcore %p;dbx \- %p"\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:OnOutOfMemoryError=\fIstring\fR +.br +Sets a custom command or a series of semicolon-separated commands to run when an \f3OutOfMemoryError\fR exception is first thrown\&. If the string contains spaces, then it must be enclosed in quotation marks\&. For an example of a command string, see the description of the \f3-XX:OnError\fR option\&. +.TP +-XX:+PerfDataSaveToFile +.br +If enabled, saves jstat(1) binary data when the Java application exits\&. This binary data is saved in a file named \f3hsperfdata_\fR\fI\fR, where \fI\fR is the process identifier of the Java application you ran\&. Use \f3jstat\fR to display the performance data contained in this file as follows: +.sp +.nf +\f3jstat \-class file:///\fI\fR/hsperfdata_\fI\fR\fP +.fi +.nf +\f3jstat \-gc file:///\fI\fR/hsperfdata_\fI\fR\fP +.fi +.sp + +.TP +-XX:+PrintCommandLineFlags +.br +Enables printing of ergonomically selected JVM flags that appeared on the command line\&. It can be useful to know the ergonomic values set by the JVM, such as the heap space size and the selected garbage collector\&. By default, this option is disabled and flags are not printed\&. +.TP +-XX:+PrintNMTStatistics +.br +Enables printing of collected native memory tracking data at JVM exit when native memory tracking is enabled (see \f3-XX:NativeMemoryTracking\fR)\&. By default, this option is disabled and native memory tracking data is not printed\&. +.TP +-XX:+RelaxAccessControlCheck +.br Decreases the amount of access control checks in the verifier\&. By default, this option is disabled, and it is ignored (that is, treated as disabled) for classes with a recent bytecode version\&. You can enable it for classes with older versions of the bytecode\&. -.RE -.PP -\-XX:+ShowMessageBoxOnError -.RS 4 +.TP +-XX:+ShowMessageBoxOnError +.br Enables displaying of a dialog box when the JVM experiences an irrecoverable error\&. This prevents the JVM from exiting and keeps the process active so that you can attach a debugger to it to investigate the cause of the error\&. By default, this option is disabled\&. -.RE -.PP -\-XX:ThreadStackSize=\fIsize\fR -.RS 4 -Sets the thread stack size (in bytes)\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. The default value depends on the platform: -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Linux/ARM (32\-bit): 320 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Linux/i386 (32\-bit): 320 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Linux/x64 (64\-bit): 1024 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -OS X (64\-bit): 1024 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Oracle Solaris/i386 (32\-bit): 320 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -Oracle Solaris/x64 (64\-bit): 1024 KB -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP +-XX:ThreadStackSize=\fIsize\fR +.br +Sets the thread stack size (in bytes)\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. The default value depends on the platform: +.RS +.TP 0.2i +\(bu +Linux/ARM (32-bit): 320 KB +.TP 0.2i +\(bu +Linux/i386 (32-bit): 320 KB +.TP 0.2i +\(bu +Linux/x64 (64-bit): 1024 KB +.TP 0.2i +\(bu +OS X (64-bit): 1024 KB +.TP 0.2i +\(bu +Oracle Solaris/i386 (32-bit): 320 KB +.TP 0.2i +\(bu +Oracle Solaris/x64 (64-bit): 1024 KB +.TP 0.2i +\(bu Windows: depends on virtual memory -.RE -.sp +.RE + + The following examples show how to set the thread stack size to 1024 KB in different units: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:ThreadStackSize=1m\fR -\fB\-XX:ThreadStackSize=1024k\fR -\fB\-XX:ThreadStackSize=1048576\fR - -.fi -.if n \{\ -.RE -.\} -This option is equivalent to -\fB\-Xss\fR\&. -.RE -.PP -\-XX:+TraceClassLoading -.RS 4 +.sp +.nf +\f3\-XX:ThreadStackSize=1m\fP +.fi +.nf +\f3\-XX:ThreadStackSize=1024k\fP +.fi +.nf +\f3\-XX:ThreadStackSize=1048576\fP +.fi +.nf +\f3\fP +.fi +.sp + + +This option is equivalent to \f3-Xss\fR\&. +.TP +-XX:+TraceClassLoading +.br Enables tracing of classes as they are loaded\&. By default, this option is disabled and classes are not traced\&. -.RE -.PP -\-XX:+TraceClassLoadingPreorder -.RS 4 +.TP +-XX:+TraceClassLoadingPreorder +.br Enables tracing of all loaded classes in the order in which they are referenced\&. By default, this option is disabled and classes are not traced\&. -.RE -.PP -\-XX:+TraceClassResolution -.RS 4 +.TP +-XX:+TraceClassResolution +.br Enables tracing of constant pool resolutions\&. By default, this option is disabled and constant pool resolutions are not traced\&. -.RE -.PP -\-XX:+TraceClassUnloading -.RS 4 +.TP +-XX:+TraceClassUnloading +.br Enables tracing of classes as they are unloaded\&. By default, this option is disabled and classes are not traced\&. -.RE -.PP -\-XX:+TraceLoaderConstraints -.RS 4 +.TP +-XX:+TraceLoaderConstraints +.br Enables tracing of the loader constraints recording\&. By default, this option is disabled and loader constraints recording is not traced\&. -.RE -.PP -\-XX:+UseAltSigs -.RS 4 -Enables the use of alternative signals instead of -\fBSIGUSR1\fR -and -\fBSIGUSR2\fR -for JVM internal signals\&. By default, this option is disabled and alternative signals are not used\&. This option is equivalent to -\fB\-Xusealtsigs\fR\&. -.RE -.PP -\-XX:\-UseBiasedLocking -.RS 4 -Disables the use of biased locking\&. Some applications with significant amounts of uncontended synchronization may attain significant speedups with this flag enabled, whereas applications with certain patterns of locking may see slowdowns\&. For more information about the biased locking technique, see the example in Java Tuning White Paper at http://www\&.oracle\&.com/technetwork/java/tuning\-139912\&.html#section4\&.2\&.5 -.sp +.TP +-XX:+UseAltSigs +.br +Enables the use of alternative signals instead of \f3SIGUSR1\fR and \f3SIGUSR2\fR for JVM internal signals\&. By default, this option is disabled and alternative signals are not used\&. This option is equivalent to \f3-Xusealtsigs\fR\&. +.TP +-XX:-UseBiasedLocking +.br +Disables the use of biased locking\&. Some applications with significant amounts of uncontended synchronization may attain significant speedups with this flag enabled, whereas applications with certain patterns of locking may see slowdowns\&. For more information about the biased locking technique, see the example in Java Tuning White Paper at http://www\&.oracle\&.com/technetwork/java/tuning-139912\&.html#section4\&.2\&.5 + By default, this option is enabled\&. -.RE -.PP -\-XX:\-UseCompressedOops -.RS 4 -Disables the use of compressed pointers\&. By default, this option is enabled, and compressed pointers are used when Java heap sizes are less than 32 GB\&. When this option is enabled, object references are represented as 32\-bit offsets instead of 64\-bit pointers, which typically increases performance when running the application with Java heap sizes less than 32 GB\&. This option works only for 64\-bit JVMs\&. -.RE -.PP -\-XX:\-UseLargePages -.RS 4 -Disables the use of large page memory\&. This option is enabled by default\&. -.sp -For more information, see Java Support for Large Memory Pages at http://www\&.oracle\&.com/technetwork/java/javase/tech/largememory\-jsp\-137182\&.html -.RE -.PP -\-XX:+UseMembar -.RS 4 +.TP +-XX:-UseCompressedOops +.br +Disables the use of compressed pointers\&. By default, this option is enabled, and compressed pointers are used when Java heap sizes are less than 32 GB\&. When this option is enabled, object references are represented as 32-bit offsets instead of 64-bit pointers, which typically increases performance when running the application with Java heap sizes less than 32 GB\&. This option works only for 64-bit JVMs\&. + +It is also possible to use compressed pointers when Java heap sizes are greater than 32GB\&. See the \f3-XX:ObjectAlignmentInBytes\fR option\&. +.TP +-XX:+UseHugeTLBFS +.br +This option for Linux is the equivalent of specifying \f3-XX:+UseLargePages\fR\&. This option is disabled by default\&. This option pre-allocates all large pages up-front, when memory is reserved; consequently the JVM cannot dynamically grow or shrink large pages memory areas; see \f3-XX:UseTransparentHugePages\fR if you want this behavior\&. + +For more information, see Large Pages\&. +.TP +-XX:+UseLargePages +.br +Enables the use of large page memory\&. By default, this option is disabled and large page memory is not used\&. + +For more information, see Large Pages\&. +.TP +-XX:+UseMembar +.br Enables issuing of membars on thread state transitions\&. This option is disabled by default on all platforms except ARM servers, where it is enabled\&. (It is recommended that you do not disable this option on ARM servers\&.) -.RE -.PP -\-XX:+UsePerfData -.RS 4 -Enables the -\fBperfdata\fR -feature\&. This option is enabled by default to allow JVM monitoring and performance testing\&. Disabling it suppresses the creation of the -\fBhsperfdata_userid\fR -directories\&. To disable the -\fBperfdata\fR -feature, specify -\fB\-XX:\-UsePerfData\fR\&. -.RE -.PP -\-XX:+AllowUserSignalHandlers -.RS 4 +.TP +-XX:+UsePerfData +.br +Enables the \f3perfdata\fR feature\&. This option is enabled by default to allow JVM monitoring and performance testing\&. Disabling it suppresses the creation of the \f3hsperfdata_userid\fR directories\&. To disable the \f3perfdata\fR feature, specify \f3-XX:-UsePerfData\fR\&. +.TP +-XX:+UseTransparentHugePages +.br +On Linux, enables the use of large pages that can dynamically grow or shrink\&. This option is disabled by default\&. You may encounter performance problems with transparent huge pages as the OS moves other pages around to create huge pages; this option is made available for experimentation\&. + +For more information, see Large Pages\&. +.TP +-XX:+AllowUserSignalHandlers +.br Enables installation of signal handlers by the application\&. By default, this option is disabled and the application is not allowed to install signal handlers\&. -.RE -.SS "Advanced JIT Compiler Options" -.PP -These options control the dynamic just\-in\-time (JIT) compilation performed by the Java HotSpot VM\&. -.PP -\-XX:+AggressiveOpts -.RS 4 +.SS ADVANCED\ JIT\ COMPILER\ OPTIONS +These options control the dynamic just-in-time (JIT) compilation performed by the Java HotSpot VM\&. +.TP +-XX:+AggressiveOpts +.br Enables the use of aggressive performance optimization features, which are expected to become default in upcoming releases\&. By default, this option is disabled and experimental performance features are not used\&. -.RE -.PP -\-XX:AllocateInstancePrefetchLines=\fIlines\fR -.RS 4 +.TP +-XX:AllocateInstancePrefetchLines=\fIlines\fR +.br Sets the number of lines to prefetch ahead of the instance allocation pointer\&. By default, the number of lines to prefetch is set to 1: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:AllocateInstancePrefetchLines=1\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3\-XX:AllocateInstancePrefetchLines=1\fP +.fi +.nf +\f3\fP +.fi +.sp + + Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:AllocatePrefetchDistance=\fIsize\fR -.RS 4 +.TP +-XX:AllocatePrefetchDistance=\fIsize\fR +.br Sets the size (in bytes) of the prefetch distance for object allocation\&. Memory about to be written with the value of new objects is prefetched up to this distance starting from the address of the last allocated object\&. Each Java thread has its own allocation point\&. -.sp -Negative values denote that prefetch distance is chosen based on the platform\&. Positive values are bytes to prefetch\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. The default value is set to \-1\&. -.sp + +Negative values denote that prefetch distance is chosen based on the platform\&. Positive values are bytes to prefetch\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. The default value is set to -1\&. + The following example shows how to set the prefetch distance to 1024 bytes: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:AllocatePrefetchDistance=1024\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3\-XX:AllocatePrefetchDistance=1024\fP +.fi +.nf +\f3\fP +.fi +.sp + + Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:AllocatePrefetchInstr=\fIinstruction\fR -.RS 4 +.TP +-XX:AllocatePrefetchInstr=\fIinstruction\fR +.br Sets the prefetch instruction to prefetch ahead of the allocation pointer\&. Only the Java HotSpot Server VM supports this option\&. Possible values are from 0 to 3\&. The actual instructions behind the values depend on the platform\&. By default, the prefetch instruction is set to 0: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:AllocatePrefetchInstr=0\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3\-XX:AllocatePrefetchInstr=0\fP +.fi +.nf +\f3\fP +.fi +.sp + + Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:AllocatePrefetchLines=\fIlines\fR -.RS 4 +.TP +-XX:AllocatePrefetchLines=\fIlines\fR +.br Sets the number of cache lines to load after the last object allocation by using the prefetch instructions generated in compiled code\&. The default value is 1 if the last allocated object was an instance, and 3 if it was an array\&. -.sp + The following example shows how to set the number of loaded cache lines to 5: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:AllocatePrefetchLines=5\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3\-XX:AllocatePrefetchLines=5\fP +.fi +.nf +\f3\fP +.fi +.sp + + Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:AllocatePrefetchStepSize=\fIsize\fR -.RS 4 -Sets the step size (in bytes) for sequential prefetch instructions\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. By default, the step size is set to 16 bytes: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:AllocatePrefetchStepSize=16\fR - -.fi -.if n \{\ -.RE -.\} +.TP +-XX:AllocatePrefetchStepSize=\fIsize\fR +.br +Sets the step size (in bytes) for sequential prefetch instructions\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. By default, the step size is set to 16 bytes: +.sp +.nf +\f3\-XX:AllocatePrefetchStepSize=16\fP +.fi +.nf +\f3\fP +.fi +.sp + + Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:AllocatePrefetchStyle=\fIstyle\fR -.RS 4 -Sets the generated code style for prefetch instructions\&. The -\fIstyle\fR -argument is an integer from 0 to 3: -.PP +.TP +-XX:AllocatePrefetchStyle=\fIstyle\fR +.br +Sets the generated code style for prefetch instructions\&. The \fIstyle\fR argument is an integer from 0 to 3: +.RS +.TP 0 -.RS 4 Do not generate prefetch instructions\&. -.RE -.PP +.TP 1 -.RS 4 Execute prefetch instructions after each allocation\&. This is the default parameter\&. -.RE -.PP +.TP 2 -.RS 4 -Use the thread\-local allocation block (TLAB) watermark pointer to determine when prefetch instructions are executed\&. -.RE -.PP +Use the thread-local allocation block (TLAB) watermark pointer to determine when prefetch instructions are executed\&. +.TP 3 -.RS 4 Use BIS instruction on SPARC for allocation prefetch\&. -.RE -.sp +.RE + + Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:+BackgroundCompilation -.RS 4 -Enables background compilation\&. This option is enabled by default\&. To disable background compilation, specify -\fB\-XX:\-BackgroundCompilation\fR -(this is equivalent to specifying -\fB\-Xbatch\fR)\&. -.RE -.PP -\-XX:CICompilerCount=\fIthreads\fR -.RS 4 +.TP +-XX:+BackgroundCompilation +.br +Enables background compilation\&. This option is enabled by default\&. To disable background compilation, specify \f3-XX:-BackgroundCompilation\fR (this is equivalent to specifying \f3-Xbatch\fR)\&. +.TP +-XX:CICompilerCount=\fIthreads\fR +.br Sets the number of compiler threads to use for compilation\&. By default, the number of threads is set to 2 for the server JVM, to 1 for the client JVM, and it scales to the number of cores if tiered compilation is used\&. The following example shows how to set the number of threads to 2: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CICompilerCount=2\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:CodeCacheMinimumFreeSpace=\fIsize\fR -.RS 4 -Sets the minimum free space (in bytes) required for compilation\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. When less than the minimum free space remains, compiling stops\&. By default, this option is set to 500 KB\&. The following example shows how to set the minimum free space to 1024 MB: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CodeCacheMinimumFreeSpace=1024m\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:CompileCommand=\fIcommand\fR,\fImethod\fR[,\fIoption\fR] -.RS 4 -Specifies a command to perform on a method\&. For example, to exclude the -\fBindexOf()\fR -method of the -\fBString\fR -class from being compiled, use the following: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileCommand=exclude,java/lang/String\&.indexOf\fR - -.fi -.if n \{\ -.RE -.\} -Note that the full class name is specified, including all packages and subpackages separated by a slash (\fB/\fR)\&. For easier cut and paste operations, it is also possible to use the method name format produced by the -\fB\-XX:+PrintCompilation\fR -and -\fB\-XX:+LogCompilation\fR -options: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileCommand=exclude,java\&.lang\&.String::indexOf\fR - -.fi -.if n \{\ -.RE -.\} -If the method is specified without the signature, the command will be applied to all methods with the specified name\&. However, you can also specify the signature of the method in the class file format\&. In this case, you should enclose the arguments in quotation marks, because otherwise the shell treats the semicolon as command end\&. For example, if you want to exclude only the -\fBindexOf(String)\fR -method of the -\fBString\fR -class from being compiled, use the following: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileCommand="exclude,java/lang/String\&.indexOf,(Ljava/lang/String;)I"\fR - -.fi -.if n \{\ -.RE -.\} -You can also use the asterisk (*) as a wildcard for class and method names\&. For example, to exclude all -\fBindexOf()\fR -methods in all classes from being compiled, use the following: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileCommand=exclude,*\&.indexOf\fR - -.fi -.if n \{\ -.RE -.\} -The commas and periods are aliases for spaces, making it easier to pass compiler commands through a shell\&. You can pass arguments to -\fB\-XX:CompileCommand\fR -using spaces as separators by enclosing the argument in quotation marks: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileCommand="exclude java/lang/String indexOf"\fR - -.fi -.if n \{\ -.RE -.\} -Note that after parsing the commands passed on the command line using the -\fB\-XX:CompileCommand\fR -options, the JIT compiler then reads commands from the -\fB\&.hotspot_compiler\fR -file\&. You can add commands to this file or specify a different file using the -\fB\-XX:CompileCommandFile\fR -option\&. -.sp -To add several commands, either specify the -\fB\-XX:CompileCommand\fR -option multiple times, or separate each argument with the newline separator (\fB\en\fR)\&. The following commands are available: -.PP +.sp +.nf +\f3\-XX:CICompilerCount=2\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:CodeCacheMinimumFreeSpace=\fIsize\fR +.br +Sets the minimum free space (in bytes) required for compilation\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. When less than the minimum free space remains, compiling stops\&. By default, this option is set to 500 KB\&. The following example shows how to set the minimum free space to 1024 MB: +.sp +.nf +\f3\-XX:CodeCacheMinimumFreeSpace=1024m\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:CompileCommand=\fIcommand\fR,\fImethod\fR[,\fIoption\fR] +.br +Specifies a command to perform on a method\&. For example, to exclude the \f3indexOf()\fR method of the \f3String\fR class from being compiled, use the following: +.sp +.nf +\f3\-XX:CompileCommand=exclude,java/lang/String\&.indexOf\fP +.fi +.nf +\f3\fP +.fi +.sp + + +Note that the full class name is specified, including all packages and subpackages separated by a slash (\f3/\fR)\&. For easier cut and paste operations, it is also possible to use the method name format produced by the \f3-XX:+PrintCompilation\fR and \f3-XX:+LogCompilation\fR options: +.sp +.nf +\f3\-XX:CompileCommand=exclude,java\&.lang\&.String::indexOf\fP +.fi +.nf +\f3\fP +.fi +.sp + + +If the method is specified without the signature, the command will be applied to all methods with the specified name\&. However, you can also specify the signature of the method in the class file format\&. In this case, you should enclose the arguments in quotation marks, because otherwise the shell treats the semicolon as command end\&. For example, if you want to exclude only the \f3indexOf(String)\fR method of the \f3String\fR class from being compiled, use the following: +.sp +.nf +\f3\-XX:CompileCommand="exclude,java/lang/String\&.indexOf,(Ljava/lang/String;)I"\fP +.fi +.nf +\f3\fP +.fi +.sp + + +You can also use the asterisk (*) as a wildcard for class and method names\&. For example, to exclude all \f3indexOf()\fR methods in all classes from being compiled, use the following: +.sp +.nf +\f3\-XX:CompileCommand=exclude,*\&.indexOf\fP +.fi +.nf +\f3\fP +.fi +.sp + + +The commas and periods are aliases for spaces, making it easier to pass compiler commands through a shell\&. You can pass arguments to \f3-XX:CompileCommand\fR using spaces as separators by enclosing the argument in quotation marks: +.sp +.nf +\f3\-XX:CompileCommand="exclude java/lang/String indexOf"\fP +.fi +.nf +\f3\fP +.fi +.sp + + +Note that after parsing the commands passed on the command line using the \f3-XX:CompileCommand\fR options, the JIT compiler then reads commands from the \f3\&.hotspot_compiler\fR file\&. You can add commands to this file or specify a different file using the \f3-XX:CompileCommandFile\fR option\&. + +To add several commands, either specify the \f3-XX:CompileCommand\fR option multiple times, or separate each argument with the newline separator (\f3\en\fR)\&. The following commands are available: +.RS +.TP break -.RS 4 Set a breakpoint when debugging the JVM to stop at the beginning of compilation of the specified method\&. -.RE -.PP +.TP compileonly -.RS 4 -Exclude all methods from compilation except for the specified method\&. As an alternative, you can use the -\fB\-XX:CompileOnly\fR -option, which allows to specify several methods\&. -.RE -.PP +Exclude all methods from compilation except for the specified method\&. As an alternative, you can use the \f3-XX:CompileOnly\fR option, which allows to specify several methods\&. +.TP dontinline -.RS 4 Prevent inlining of the specified method\&. -.RE -.PP +.TP exclude -.RS 4 Exclude the specified method from compilation\&. -.RE -.PP +.TP help -.RS 4 -Print a help message for the -\fB\-XX:CompileCommand\fR -option\&. -.RE -.PP +Print a help message for the \f3-XX:CompileCommand\fR option\&. +.TP inline -.RS 4 Attempt to inline the specified method\&. -.RE -.PP +.TP log -.RS 4 -Exclude compilation logging (with the -\fB\-XX:+LogCompilation\fR -option) for all methods except for the specified method\&. By default, logging is performed for all compiled methods\&. -.RE -.PP +Exclude compilation logging (with the \f3-XX:+LogCompilation\fR option) for all methods except for the specified method\&. By default, logging is performed for all compiled methods\&. +.TP option -.RS 4 -This command can be used to pass a JIT compilation option to the specified method in place of the last argument (\fIoption\fR)\&. The compilation option is set at the end, after the method name\&. For example, to enable the -\fBBlockLayoutByFrequency\fR -option for the -\fBappend()\fR -method of the -\fBStringBuffer\fR -class, use the following: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileCommand=option,java/lang/StringBuffer\&.append,BlockLayoutByFrequency\fR - -.fi -.if n \{\ -.RE -.\} +This command can be used to pass a JIT compilation option to the specified method in place of the last argument (\fIoption\fR)\&. The compilation option is set at the end, after the method name\&. For example, to enable the \f3BlockLayoutByFrequency\fR option for the \f3append()\fR method of the \f3StringBuffer\fR class, use the following: +.sp +.nf +\f3\-XX:CompileCommand=option,java/lang/StringBuffer\&.append,BlockLayoutByFrequency\fP +.fi +.nf +\f3\fP +.fi +.sp + + You can specify multiple compilation options, separated by commas or spaces\&. -.RE -.PP +.TP print -.RS 4 Print generated assembler code after compilation of the specified method\&. -.RE -.PP +.TP quiet -.RS 4 -Do not print the compile commands\&. By default, the commands that you specify with the \-\fBXX:CompileCommand\fR -option are printed; for example, if you exclude from compilation the -\fBindexOf()\fR -method of the -\fBString\fR -class, then the following will be printed to standard output: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBCompilerOracle: exclude java/lang/String\&.indexOf\fR - -.fi -.if n \{\ -.RE -.\} -You can suppress this by specifying the -\fB\-XX:CompileCommand=quiet\fR -option before other -\fB\-XX:CompileCommand\fR -options\&. -.RE -.RE -.PP -\-XX:CompileCommandFile=\fIfilename\fR -.RS 4 -Sets the file from which JIT compiler commands are read\&. By default, the -\fB\&.hotspot_compiler\fR -file is used to store commands performed by the JIT compiler\&. -.sp -Each line in the command file represents a command, a class name, and a method name for which the command is used\&. For example, this line prints assembly code for the -\fBtoString()\fR -method of the -\fBString\fR -class: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBprint java/lang/String toString\fR - -.fi -.if n \{\ -.RE -.\} -For more information about specifying the commands for the JIT compiler to perform on methods, see the -\fB\-XX:CompileCommand\fR -option\&. -.RE -.PP -\-XX:CompileOnly=\fImethods\fR -.RS 4 -Sets the list of methods (separated by commas) to which compilation should be restricted\&. Only the specified methods will be compiled\&. Specify each method with the full class name (including the packages and subpackages)\&. For example, to compile only the -\fBlength()\fR -method of the -\fBString\fR -class and the -\fBsize()\fR -method of the -\fBList\fR -class, use the following: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileOnly=java/lang/String\&.length,java/util/List\&.size\fR - -.fi -.if n \{\ -.RE -.\} -Note that the full class name is specified, including all packages and subpackages separated by a slash (\fB/\fR)\&. For easier cut and paste operations, it is also possible to use the method name format produced by the -\fB\-XX:+PrintCompilation\fR -and -\fB\-XX:+LogCompilation\fR -options: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileOnly=java\&.lang\&.String::length,java\&.util\&.List::size\fR - -.fi -.if n \{\ -.RE -.\} +Do not print the compile commands\&. By default, the commands that you specify with the -\f3XX:CompileCommand\fR option are printed; for example, if you exclude from compilation the \f3indexOf()\fR method of the \f3String\fR class, then the following will be printed to standard output: +.sp +.nf +\f3CompilerOracle: exclude java/lang/String\&.indexOf\fP +.fi +.nf +\f3\fP +.fi +.sp + + +You can suppress this by specifying the \f3-XX:CompileCommand=quiet\fR option before other \f3-XX:CompileCommand\fR options\&. +.RE + +.TP +-XX:CompileCommandFile=\fIfilename\fR +.br +Sets the file from which JIT compiler commands are read\&. By default, the \f3\&.hotspot_compiler\fR file is used to store commands performed by the JIT compiler\&. + +Each line in the command file represents a command, a class name, and a method name for which the command is used\&. For example, this line prints assembly code for the \f3toString()\fR method of the \f3String\fR class: +.sp +.nf +\f3print java/lang/String toString\fP +.fi +.nf +\f3\fP +.fi +.sp + + +For more information about specifying the commands for the JIT compiler to perform on methods, see the \f3-XX:CompileCommand\fR option\&. +.TP +-XX:CompileOnly=\fImethods\fR +.br +Sets the list of methods (separated by commas) to which compilation should be restricted\&. Only the specified methods will be compiled\&. Specify each method with the full class name (including the packages and subpackages)\&. For example, to compile only the \f3length()\fR method of the \f3String\fR class and the \f3size()\fR method of the \f3List\fR class, use the following: +.sp +.nf +\f3\-XX:CompileOnly=java/lang/String\&.length,java/util/List\&.size\fP +.fi +.nf +\f3\fP +.fi +.sp + + +Note that the full class name is specified, including all packages and subpackages separated by a slash (\f3/\fR)\&. For easier cut and paste operations, it is also possible to use the method name format produced by the \f3-XX:+PrintCompilation\fR and \f3-XX:+LogCompilation\fR options: +.sp +.nf +\f3\-XX:CompileOnly=java\&.lang\&.String::length,java\&.util\&.List::size\fP +.fi +.nf +\f3\fP +.fi +.sp + + Although wildcards are not supported, you can specify only the class or package name to compile all methods in that class or package, as well as specify just the method to compile methods with this name in any class: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileOnly=java/lang/String\fR -\fB\-XX:CompileOnly=java/lang\fR -\fB\-XX:CompileOnly=\&.length\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:CompileThreshold=\fIinvocations\fR -.RS 4 -Sets the number of interpreted method invocations before compilation\&. By default, in the server JVM, the JIT compiler performs 10,000 interpreted method invocations to gather information for efficient compilation\&. For the client JVM, the default setting is 1,500 invocations\&. The following example shows how to set the number of interpreted method invocations to 5,000: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CompileThreshold=5000\fR - -.fi -.if n \{\ -.RE -.\} -You can completely disable interpretation of Java methods before compilation by specifying the -\fB\-Xcomp\fR -option\&. -.RE -.PP -\-XX:+DoEscapeAnalysis -.RS 4 -Enables the use of escape analysis\&. This option is enabled by default\&. To disable the use of escape analysis, specify -\fB\-XX:\-DoEscapeAnalysis\fR\&. Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:InitialCodeCacheSize=\fIsize\fR -.RS 4 -Sets the initial code cache size (in bytes)\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. The default value is set to 500 KB\&. The following example shows how to set the initial code cache size to 32 KB: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:InitialCodeCacheSize=32k\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:+Inline -.RS 4 -Enables method inlining\&. This option is enabled by default to increase performance\&. To disable method inlining, specify -\fB\-XX:\-Inline\fR\&. -.RE -.PP -\-XX:InlineSmallCode=\fIsize\fR -.RS 4 -Sets the maximum code size (in bytes) for compiled methods that should be inlined\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. Only compiled methods with the size smaller than the specified size will be inlined\&. By default, the maximum code size is set to 1000 bytes: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:InlineSmallCode=1000\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:+LogCompilation -.RS 4 -Enables logging of compilation activity to a file named -\fBhotspot\&.log\fR -in the current working directory\&. You can specify a different log file path and name using the -\fB\-XX:LogFile\fR -option\&. -.sp -By default, this option is disabled and compilation activity is not logged\&. The -\fB\-XX:+LogCompilation\fR -option has to be used together with the -\fB\-XX:UnlockDiagnosticVMOptions\fR -option that unlocks diagnostic JVM options\&. -.sp -You can enable verbose diagnostic output with a message printed to the console every time a method is compiled by using the -\fB\-XX:+PrintCompilation\fR -option\&. -.RE -.PP -\-XX:MaxInlineSize=\fIsize\fR -.RS 4 -Sets the maximum bytecode size (in bytes) of a method to be inlined\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. By default, the maximum bytecode size is set to 35 bytes: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MaxInlineSize=35\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:MaxNodeLimit=\fInodes\fR -.RS 4 +.sp +.nf +\f3\-XX:CompileOnly=java/lang/String\fP +.fi +.nf +\f3\-XX:CompileOnly=java/lang\fP +.fi +.nf +\f3\-XX:CompileOnly=\&.length\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:CompileThreshold=\fIinvocations\fR +.br +Sets the number of interpreted method invocations before compilation\&. By default, in the server JVM, the JIT compiler performs 10,000 interpreted method invocations to gather information for efficient compilation\&. For the client JVM, the default setting is 1,500 invocations\&. This option is ignored when tiered compilation is enabled; see the option \f3-XX:+TieredCompilation\fR\&. The following example shows how to set the number of interpreted method invocations to 5,000: +.sp +.nf +\f3\-XX:CompileThreshold=5000\fP +.fi +.nf +\f3\fP +.fi +.sp + + +You can completely disable interpretation of Java methods before compilation by specifying the \f3-Xcomp\fR option\&. +.TP +-XX:+DoEscapeAnalysis +.br +Enables the use of escape analysis\&. This option is enabled by default\&. To disable the use of escape analysis, specify \f3-XX:-DoEscapeAnalysis\fR\&. Only the Java HotSpot Server VM supports this option\&. +.TP +-XX:InitialCodeCacheSize=\fIsize\fR +.br +Sets the initial code cache size (in bytes)\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. The default value is set to 500 KB\&. The initial code cache size should be not less than the system\&'s minimal memory page size\&. The following example shows how to set the initial code cache size to 32 KB: +.sp +.nf +\f3\-XX:InitialCodeCacheSize=32k\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:+Inline +.br +Enables method inlining\&. This option is enabled by default to increase performance\&. To disable method inlining, specify \f3-XX:-Inline\fR\&. +.TP +-XX:InlineSmallCode=\fIsize\fR +.br +Sets the maximum code size (in bytes) for compiled methods that should be inlined\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. Only compiled methods with the size smaller than the specified size will be inlined\&. By default, the maximum code size is set to 1000 bytes: +.sp +.nf +\f3\-XX:InlineSmallCode=1000\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:+LogCompilation +.br +Enables logging of compilation activity to a file named \f3hotspot\&.log\fR in the current working directory\&. You can specify a different log file path and name using the \f3-XX:LogFile\fR option\&. + +By default, this option is disabled and compilation activity is not logged\&. The \f3-XX:+LogCompilation\fR option has to be used together with the \f3-XX:UnlockDiagnosticVMOptions\fR option that unlocks diagnostic JVM options\&. + +You can enable verbose diagnostic output with a message printed to the console every time a method is compiled by using the \f3-XX:+PrintCompilation\fR option\&. +.TP +-XX:MaxInlineSize=\fIsize\fR +.br +Sets the maximum bytecode size (in bytes) of a method to be inlined\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. By default, the maximum bytecode size is set to 35 bytes: +.sp +.nf +\f3\-XX:MaxInlineSize=35\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:MaxNodeLimit=\fInodes\fR +.br Sets the maximum number of nodes to be used during single method compilation\&. By default, the maximum number of nodes is set to 65,000: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MaxNodeLimit=65000\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:MaxTrivialSize=\fIsize\fR -.RS 4 -Sets the maximum bytecode size (in bytes) of a trivial method to be inlined\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. By default, the maximum bytecode size of a trivial method is set to 6 bytes: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MaxTrivialSize=6\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:+OptimizeStringConcat -.RS 4 -Enables the optimization of -\fBString\fR -concatenation operations\&. This option is enabled by default\&. To disable the optimization of -\fBString\fR -concatenation operations, specify -\fB\-XX:\-OptimizeStringConcat\fR\&. Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:+PrintAssembly -.RS 4 -Enables printing of assembly code for bytecoded and native methods by using the external -\fBdisassembler\&.so\fR -library\&. This enables you to see the generated code, which may help you to diagnose performance issues\&. -.sp -By default, this option is disabled and assembly code is not printed\&. The -\fB\-XX:+PrintAssembly\fR -option has to be used together with the -\fB\-XX:UnlockDiagnosticVMOptions\fR -option that unlocks diagnostic JVM options\&. -.RE -.PP -\-XX:+PrintCompilation -.RS 4 +.sp +.nf +\f3\-XX:MaxNodeLimit=65000\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:MaxTrivialSize=\fIsize\fR +.br +Sets the maximum bytecode size (in bytes) of a trivial method to be inlined\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. By default, the maximum bytecode size of a trivial method is set to 6 bytes: +.sp +.nf +\f3\-XX:MaxTrivialSize=6\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:+OptimizeStringConcat +.br +Enables the optimization of \f3String\fR concatenation operations\&. This option is enabled by default\&. To disable the optimization of \f3String\fR concatenation operations, specify \f3-XX:-OptimizeStringConcat\fR\&. Only the Java HotSpot Server VM supports this option\&. +.TP +-XX:+PrintAssembly +.br +Enables printing of assembly code for bytecoded and native methods by using the external \f3disassembler\&.so\fR library\&. This enables you to see the generated code, which may help you to diagnose performance issues\&. + +By default, this option is disabled and assembly code is not printed\&. The \f3-XX:+PrintAssembly\fR option has to be used together with the \f3-XX:UnlockDiagnosticVMOptions\fR option that unlocks diagnostic JVM options\&. +.TP +-XX:+PrintCompilation +.br Enables verbose diagnostic output from the JVM by printing a message to the console every time a method is compiled\&. This enables you to see which methods actually get compiled\&. By default, this option is disabled and diagnostic output is not printed\&. -.sp -You can also log compilation activity to a file by using the -\fB\-XX:+LogCompilation\fR -option\&. -.RE -.PP -\-XX:+PrintInlining -.RS 4 + +You can also log compilation activity to a file by using the \f3-XX:+LogCompilation\fR option\&. +.TP +-XX:+PrintInlining +.br Enables printing of inlining decisions\&. This enables you to see which methods are getting inlined\&. -.sp -By default, this option is disabled and inlining information is not printed\&. The -\fB\-XX:+PrintInlining\fR -option has to be used together with the -\fB\-XX:+UnlockDiagnosticVMOptions\fR -option that unlocks diagnostic JVM options\&. -.RE -.PP -\-XX:ReservedCodeCacheSize=\fIsize\fR -.RS 4 -Sets the maximum code cache size (in bytes) for JIT\-compiled code\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. This option is equivalent to -\fB\-Xmaxjitcodesize\fR\&. -.RE -.PP -\-XX:+TieredCompilation -.RS 4 + +By default, this option is disabled and inlining information is not printed\&. The \f3-XX:+PrintInlining\fR option has to be used together with the \f3-XX:+UnlockDiagnosticVMOptions\fR option that unlocks diagnostic JVM options\&. +.TP +-XX:ReservedCodeCacheSize=\fIsize\fR +.br +Sets the maximum code cache size (in bytes) for JIT-compiled code\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. This option has a limit of 2 GB; otherwise, an error is generated\&. The maximum code cache size should not be less than the initial code cache size; see the option \f3-XX:InitialCodeCacheSize\fR\&. This option is equivalent to \f3-Xmaxjitcodesize\fR\&. +.TP +-XX:RTMAbortRatio=\fIabort_ratio\fR +.br +The RTM abort ratio is specified as a percentage (%) of all executed RTM transactions\&. If a number of aborted transactions becomes greater than this ratio, then the compiled code will be deoptimized\&. This ratio is used when the \f3-XX:+UseRTMDeopt\fR option is enabled\&. The default value of this option is 50\&. This means that the compiled code will be deoptimized if 50% of all transactions are aborted\&. +.TP +-XX:RTMRetryCount=\fInumber_of_retries\fR +.br +RTM locking code will be retried, when it is aborted or busy, the number of times specified by this option before falling back to the normal locking mechanism\&. The default value for this option is 5\&. The \f3-XX:UseRTMLocking\fR option must be enabled\&. +.TP +-XX:+TieredCompilation +.br Enables the use of tiered compilation\&. By default, this option is enabled\&. Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:+UseAES -.RS 4 -Enables hardware\-based AES intrinsics for Intel, AMD, and SPARC hardware\&. Intel Westmere (2010 and newer), AMD Bulldozer (2011 and newer), and SPARC (T4 and newer) are the supported hardware\&. UseAES is used in conjunction with UseAESIntrinsics\&. -.RE -.PP -\-XX:+UseAESIntrinsics -.RS 4 -UseAES and UseAESIntrinsics flags are enabled by default and are supported only for Java HotSpot Server VM 32\-bit and 64\-bit\&. To disable hardware\-based AES intrinsics, specify -\fB\-XX:\-UseAES \-XX:\-UseAESIntrinsics\fR\&. For example, to enable hardware AES, use the following flags: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:+UseAES \-XX:+UseAESIntrinsics\fR - -.fi -.if n \{\ -.RE -.\} -To support UseAES and UseAESIntrinsics flags for 32\-bit and 64\-bit use -\fB\-server\fR -option to choose Java HotSpot Server VM\&. These flags are not supported on Client VM\&. -.RE -.PP -\-XX:+UseCodeCacheFlushing -.RS 4 -Enables flushing of the code cache before shutting down the compiler\&. This option is enabled by default\&. To disable flushing of the code cache before shutting down the compiler, specify -\fB\-XX:\-UseCodeCacheFlushing\fR\&. -.RE -.PP -\-XX:+UseCondCardMark -.RS 4 +.TP +-XX:+UseAES +.br +Enables hardware-based AES intrinsics for Intel, AMD, and SPARC hardware\&. Intel Westmere (2010 and newer), AMD Bulldozer (2011 and newer), and SPARC (T4 and newer) are the supported hardware\&. UseAES is used in conjunction with UseAESIntrinsics\&. +.TP +-XX:+UseAESIntrinsics +.br +UseAES and UseAESIntrinsics flags are enabled by default and are supported only for Java HotSpot Server VM 32-bit and 64-bit\&. To disable hardware-based AES intrinsics, specify \f3-XX:-UseAES -XX:-UseAESIntrinsics\fR\&. For example, to enable hardware AES, use the following flags: +.sp +.nf +\f3\-XX:+UseAES \-XX:+UseAESIntrinsics\fP +.fi +.nf +\f3\fP +.fi +.sp + + +To support UseAES and UseAESIntrinsics flags for 32-bit and 64-bit use \f3-server\fR option to choose Java HotSpot Server VM\&. These flags are not supported on Client VM\&. +.TP +-XX:+UseCodeCacheFlushing +.br +Enables flushing of the code cache before shutting down the compiler\&. This option is enabled by default\&. To disable flushing of the code cache before shutting down the compiler, specify \f3-XX:-UseCodeCacheFlushing\fR\&. +.TP +-XX:+UseCondCardMark +.br Enables checking of whether the card is already marked before updating the card table\&. This option is disabled by default and should only be used on machines with multiple sockets, where it will increase performance of Java applications that rely heavily on concurrent operations\&. Only the Java HotSpot Server VM supports this option\&. -.RE -.PP -\-XX:+UseSuperWord -.RS 4 -Enables the transformation of scalar operations into superword operations\&. This option is enabled by default\&. To disable the transformation of scalar operations into superword operations, specify -\fB\-XX:\-UseSuperWord\fR\&. Only the Java HotSpot Server VM supports this option\&. -.RE -.SS "Experimental JIT Compiler Options" -.PP -The options related to the Restricted Transactional Memory (RTM) locking feature in this section are experimental and are not officially supported in Java SE 8u20; you must enable the -\fB\-XX:+UnlockExperimentalVMOptions\fR -option to use them\&. These options are only available for the Java HotSpot Server VM on x86 CPUs that support Transactional Synchronization Extensions (TSX)\&. -.PP -\-XX:RTMAbortRatio=\fIabort_ratio\fR -.RS 4 -The RTM abort ratio is specified as a percentage (%) of all executed RTM transactions\&. If a number of aborted transactions becomes greater than this ratio, then the compiled code will be deoptimized\&. This ratio is used when the -\fB\-XX:+UseRTMDeopt\fR -option is enabled\&. The default value of this option is 50\&. This means that the compiled code will be deoptimized if 50% of all transactions are aborted\&. -.RE -.PP -\-XX:RTMRetryCount=\fInumber_of_retries\fR -.RS 4 -RTM locking code will be retried, when it is aborted or busy, the number of times specified by this option before falling back to the normal locking mechanism\&. The default value for this option is 5\&. The -\fB\-XX:UseRTMLocking\fR -option must be enabled\&. -.RE -.PP -\-XX:+UseRTMDeopt -.RS 4 -Auto\-tunes RTM locking depending on the abort ratio\&. This ratio is specified by -\fB\-XX:RTMAbortRatio\fR -option\&. If the number of aborted transactions exceeds the abort ratio, then the method containing the lock will be deoptimized and recompiled with all locks as normal locks\&. This option is disabled by default\&. The -\fB\-XX:UseRTMLocking\fR -option must be enabled\&. -.RE -.PP -\-XX:+UseRTMLocking -.RS 4 -Generate Restricted Transactional Memory (RTM) locking code for all inflated locks, with the normal locking mechanism as the fallback handler\&. This option is disabled by default\&. -.sp -RTM is part of Intel\*(Aqs Transactional Synchronization Extensions (TSX), which is an x86 instruction set extension and facilitates the creation of multithreaded applications\&. RTM introduces the new instructions -\fBXBEGIN\fR, -\fBXABORT\fR, -\fBXEND\fR, and -\fBXTEST\fR\&. The -\fBXBEGIN\fR -and -\fBXEND\fR -instructions enclose a set of instructions to run as a transaction\&. If no conflict is found when running the transaction, the memory and register modifications are committed together at the -\fBXEND\fR -instruction\&. The -\fBXABORT\fR -instruction can be used to explicitly abort a transaction and the -\fBXEND\fR -instruction to check if a set of instructions are being run in a transaction\&. -.sp -A lock on a transaction is inflated when another thread tries to access the same transaction, thereby blocking the thread that did not originally request access to the transaction\&. RTM requires that a fallback set of operations be specified in case a transaction aborts or fails\&. An RTM lock is a lock that has been delegated to the TSX\*(Aqs system\&. -.sp -RTM improves performance for highly contended locks with low conflict in a critical region (which is code that must not be accessed by more than one thread concurrently)\&. RTM also improves the performance of coarse\-grain locking, which typically does not perform well in multithreaded applications\&. (Coarse\-grain locking is the strategy of holding locks for long periods to minimize the overhead of taking and releasing locks, while fine\-grained locking is the strategy of trying to achieve maximum parallelism by locking only when necessary and unlocking as soon as possible\&.) Also, for lightly contended locks that are used by different threads, RTM can reduce false cache line sharing, also known as cache line ping\-pong\&. This occurs when multiple threads from different processors are accessing different resources, but the resources share the same cache line\&. As a result, the processors repeatedly invalidate the cache lines of other processors, which forces them to read from main memory instead of their cache\&. -.RE -.SS "Advanced Serviceability Options" -.PP +.TP +-XX:+UseRTMDeopt +.br +Auto-tunes RTM locking depending on the abort ratio\&. This ratio is specified by \f3-XX:RTMAbortRatio\fR option\&. If the number of aborted transactions exceeds the abort ratio, then the method containing the lock will be deoptimized and recompiled with all locks as normal locks\&. This option is disabled by default\&. The \f3-XX:+UseRTMLocking\fR option must be enabled\&. +.TP +-XX:+UseRTMLocking +.br +Generate Restricted Transactional Memory (RTM) locking code for all inflated locks, with the normal locking mechanism as the fallback handler\&. This option is disabled by default\&. Options related to RTM are only available for the Java HotSpot Server VM on x86 CPUs that support Transactional Synchronization Extensions (TSX)\&. + +RTM is part of Intel\&'s TSX, which is an x86 instruction set extension and facilitates the creation of multithreaded applications\&. RTM introduces the new instructions \f3XBEGIN\fR, \f3XABORT\fR, \f3XEND\fR, and \f3XTEST\fR\&. The \f3XBEGIN\fR and \f3XEND\fR instructions enclose a set of instructions to run as a transaction\&. If no conflict is found when running the transaction, the memory and register modifications are committed together at the \f3XEND\fR instruction\&. The \f3XABORT\fR instruction can be used to explicitly abort a transaction and the \f3XEND\fR instruction to check if a set of instructions are being run in a transaction\&. + +A lock on a transaction is inflated when another thread tries to access the same transaction, thereby blocking the thread that did not originally request access to the transaction\&. RTM requires that a fallback set of operations be specified in case a transaction aborts or fails\&. An RTM lock is a lock that has been delegated to the TSX\&'s system\&. + +RTM improves performance for highly contended locks with low conflict in a critical region (which is code that must not be accessed by more than one thread concurrently)\&. RTM also improves the performance of coarse-grain locking, which typically does not perform well in multithreaded applications\&. (Coarse-grain locking is the strategy of holding locks for long periods to minimize the overhead of taking and releasing locks, while fine-grained locking is the strategy of trying to achieve maximum parallelism by locking only when necessary and unlocking as soon as possible\&.) Also, for lightly contended locks that are used by different threads, RTM can reduce false cache line sharing, also known as cache line ping-pong\&. This occurs when multiple threads from different processors are accessing different resources, but the resources share the same cache line\&. As a result, the processors repeatedly invalidate the cache lines of other processors, which forces them to read from main memory instead of their cache\&. +.TP +-XX:+UseSHA +.br +Enables hardware-based intrinsics for SHA crypto hash functions for SPARC hardware\&. \f3UseSHA\fR is used in conjunction with the \f3UseSHA1Intrinsics\fR, \f3UseSHA256Intrinsics\fR, and \f3UseSHA512Intrinsics\fR options\&. + +The \f3UseSHA\fR and \f3UseSHA*Intrinsics\fR flags are enabled by default, and are supported only for Java HotSpot Server VM 64-bit on SPARC T4 and newer\&. + +This feature is only applicable when using the \f3sun\&.security\&.provider\&.Sun\fR provider for SHA operations\&. + +To disable all hardware-based SHA intrinsics, specify \f3-XX:-UseSHA\fR\&. To disable only a particular SHA intrinsic, use the appropriate corresponding option\&. For example: \f3-XX:-UseSHA256Intrinsics\fR\&. +.TP +-XX:+UseSHA1Intrinsics +.br +Enables intrinsics for SHA-1 crypto hash function\&. +.TP +-XX:+UseSHA256Intrinsics +.br +Enables intrinsics for SHA-224 and SHA-256 crypto hash functions\&. +.TP +-XX:+UseSHA512Intrinsics +.br +Enables intrinsics for SHA-384 and SHA-512 crypto hash functions\&. +.TP +-XX:+UseSuperWord +.br +Enables the transformation of scalar operations into superword operations\&. This option is enabled by default\&. To disable the transformation of scalar operations into superword operations, specify \f3-XX:-UseSuperWord\fR\&. Only the Java HotSpot Server VM supports this option\&. +.SS ADVANCED\ SERVICEABILITY\ OPTIONS These options provide the ability to gather system information and perform extensive debugging\&. -.PP -\-XX:+ExtendedDTraceProbes -.RS 4 -Enables additional -\fBdtrace\fR -tool probes that impact the performance\&. By default, this option is disabled and -\fBdtrace\fR -performs only standard probes\&. -.RE -.PP -\-XX:+HeapDumpOnOutOfMemory -.RS 4 -Enables the dumping of the Java heap to a file in the current directory by using the heap profiler (HPROF) when a -\fBjava\&.lang\&.OutOfMemoryError\fR -exception is thrown\&. You can explicitly set the heap dump file path and name using the -\fB\-XX:HeapDumpPath\fR -option\&. By default, this option is disabled and the heap is not dumped when an -\fBOutOfMemoryError\fR -exception is thrown\&. -.RE -.PP -\-XX:HeapDumpPath=\fIpath\fR -.RS 4 -Sets the path and file name for writing the heap dump provided by the heap profiler (HPROF) when the -\fB\-XX:+HeapDumpOnOutOfMemoryError\fR -option is set\&. By default, the file is created in the current working directory, and it is named -\fBjava_pid\fR\fIpid\fR\fB\&.hprof\fR -where -\fIpid\fR -is the identifier of the process that caused the error\&. The following example shows how to set the default file explicitly (\fB%p\fR -represents the current process identificator): -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:HeapDumpPath=\&./java_pid%p\&.hprof\fR - -.fi -.if n \{\ -.RE -.\} -The following example shows how to set the heap dump file to -\fB/var/log/java/java_heapdump\&.hprof\fR: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:HeapDumpPath=/var/log/java/java_heapdump\&.hprof\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:LogFile=\fIpath\fR -.RS 4 -Sets the path and file name where log data is written\&. By default, the file is created in the current working directory, and it is named -\fBhotspot\&.log\fR\&. -.sp -The following example shows how to set the log file to -\fB/var/log/java/hotspot\&.log\fR: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:LogFile=/var/log/java/hotspot\&.log\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:+PrintClassHistogram -.RS 4 -Enables printing of a class instance histogram after a -\fBControl+C\fR -event (\fBSIGTERM\fR)\&. By default, this option is disabled\&. -.sp -Setting this option is equivalent to running the -\fBjmap \-histo\fR -command, or the -\fBjcmd \fR\fIpid\fR\fB GC\&.class_histogram\fR -command, where -\fIpid\fR -is the current Java process identifier\&. -.RE -.PP -\-XX:+PrintConcurrentLocks -.RS 4 -Enables printing of j locks after a event\&. By default, this option is disabled\&. -.sp -Enables printing of j\fBava\&.util\&.concurrent\fR -locks after a -\fBControl+C\fR -event (\fBSIGTERM\fR)\&. By default, this option is disabled\&. -.sp -Setting this option is equivalent to running the -\fBjstack \-l\fR -command or the -\fBjcmd \fR\fIpid\fR\fB Thread\&.print \-l\fR -command, where -\fIpid\fR -is the current Java process identifier\&. -.RE -.PP -\-XX:+UnlockDiagnosticVMOptions -.RS 4 +.TP +-XX:+ExtendedDTraceProbes +.br +Enables additional \f3dtrace\fR tool probes that impact the performance\&. By default, this option is disabled and \f3dtrace\fR performs only standard probes\&. +.TP +-XX:+HeapDumpOnOutOfMemory +.br +Enables the dumping of the Java heap to a file in the current directory by using the heap profiler (HPROF) when a \f3java\&.lang\&.OutOfMemoryError\fR exception is thrown\&. You can explicitly set the heap dump file path and name using the \f3-XX:HeapDumpPath\fR option\&. By default, this option is disabled and the heap is not dumped when an \f3OutOfMemoryError\fR exception is thrown\&. +.TP +-XX:HeapDumpPath=\fIpath\fR +.br +Sets the path and file name for writing the heap dump provided by the heap profiler (HPROF) when the \f3-XX:+HeapDumpOnOutOfMemoryError\fR option is set\&. By default, the file is created in the current working directory, and it is named \f3java_pid\fR\fIpid\fR\f3\&.hprof\fR where \fIpid\fR is the identifier of the process that caused the error\&. The following example shows how to set the default file explicitly (\f3%p\fR represents the current process identificator): +.sp +.nf +\f3\-XX:HeapDumpPath=\&./java_pid%p\&.hprof\fP +.fi +.nf +\f3\fP +.fi +.sp + + +\fI\fRThe following example shows how to set the heap dump file to \f3/var/log/java/java_heapdump\&.hprof\fR: +.sp +.nf +\f3\-XX:HeapDumpPath=/var/log/java/java_heapdump\&.hprof\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:LogFile=\fIpath\fR +.br +Sets the path and file name where log data is written\&. By default, the file is created in the current working directory, and it is named \f3hotspot\&.log\fR\&. + +\fI\fRThe following example shows how to set the log file to \f3/var/log/java/hotspot\&.log\fR: +.sp +.nf +\f3\-XX:LogFile=/var/log/java/hotspot\&.log\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:+PrintClassHistogram +.br +\fI\fREnables printing of a class instance histogram after a \f3Control+C\fR event (\f3SIGTERM\fR)\&. By default, this option is disabled\&. + +Setting this option is equivalent to running the \f3jmap -histo\fR command, or the \f3jcmd\fR\fIpid\fR\f3GC\&.class_histogram\fR command, where \fIpid\fR is the current Java process identifier\&. +.TP +-XX:+PrintConcurrentLocks + + +Enables printing of \f3java\&.util\&.concurrent\fR locks after a \f3Control+C\fR event (\f3SIGTERM\fR)\&. By default, this option is disabled\&. + +Setting this option is equivalent to running the \f3jstack -l\fR command or the \f3jcmd\fR\fIpid\fR\f3Thread\&.print -l\fR command, where \fIpid\fR is the current Java process identifier\&. +.TP +-XX:+UnlockDiagnosticVMOptions +.br Unlocks the options intended for diagnosing the JVM\&. By default, this option is disabled and diagnostic options are not available\&. -.RE -.SS "Advanced Garbage Collection Options" -.PP -These options control how garbage collection (GC) is performed by the Java HotSpot VM\&. -.PP -\-XX:+AggressiveHeap -.RS 4 -Enables Java heap optimization\&. This sets various parameters to be optimal for long\-running jobs with intensive memory allocation, based on the configuration of the computer (RAM and CPU)\&. By default, the option is disabled and the heap is not optimized\&. -.RE -.PP -\-XX:+AlwaysPreTouch -.RS 4 -Enables touching of every page on the Java heap during JVM initialization\&. This gets all pages into the memory before entering the -\fBmain()\fR -method\&. The option can be used in testing to simulate a long\-running system with all virtual memory mapped to physical memory\&. By default, this option is disabled and all pages are committed as JVM heap space fills\&. -.RE -.PP -\-XX:+CMSClassUnloadingEnabled -.RS 4 -Enables class unloading when using the concurrent mark\-sweep (CMS) garbage collector\&. This option is enabled by default\&. To disable class unloading for the CMS garbage collector, specify -\fB\-XX:\-CMSClassUnloadingEnabled\fR\&. -.RE -.PP -\-XX:CMSExpAvgFactor=\fIpercent\fR -.RS 4 +.SS ADVANCED\ GARBAGE\ COLLECTION\ OPTIONS +These options control how garbage collection (GC) is performed by the Java HotSpot VM\&. +.TP +-XX:+AggressiveHeap +.br +Enables Java heap optimization\&. This sets various parameters to be optimal for long-running jobs with intensive memory allocation, based on the configuration of the computer (RAM and CPU)\&. By default, the option is disabled and the heap is not optimized\&. +.TP +-XX:+AlwaysPreTouch +.br +Enables touching of every page on the Java heap during JVM initialization\&. This gets all pages into the memory before entering the \f3main()\fR method\&. The option can be used in testing to simulate a long-running system with all virtual memory mapped to physical memory\&. By default, this option is disabled and all pages are committed as JVM heap space fills\&. +.TP +-XX:+CMSClassUnloadingEnabled +.br +Enables class unloading when using the concurrent mark-sweep (CMS) garbage collector\&. This option is enabled by default\&. To disable class unloading for the CMS garbage collector, specify \f3-XX:-CMSClassUnloadingEnabled\fR\&. +.TP +-XX:CMSExpAvgFactor=\fIpercent\fR +.br Sets the percentage of time (0 to 100) used to weight the current sample when computing exponential averages for the concurrent collection statistics\&. By default, the exponential averages factor is set to 25%\&. The following example shows how to set the factor to 15%: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CMSExpAvgFactor=15\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:CMSInitiatingOccupancyFraction=\fIpercent\fR -.RS 4 -Sets the percentage of the old generation occupancy (0 to 100) at which to start a CMS collection cycle\&. The default value is set to \-1\&. Any negative value (including the default) implies that -\fB\-XX:CMSTriggerRatio\fR -is used to define the value of the initiating occupancy fraction\&. -.sp +.sp +.nf +\f3\-XX:CMSExpAvgFactor=15\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:CMSInitiatingOccupancyFraction=\fIpercent\fR +.br +Sets the percentage of the old generation occupancy (0 to 100) at which to start a CMS collection cycle\&. The default value is set to -1\&. Any negative value (including the default) implies that \f3-XX:CMSTriggerRatio\fR is used to define the value of the initiating occupancy fraction\&. + The following example shows how to set the occupancy fraction to 20%: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CMSInitiatingOccupancyFraction=20\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:+CMSScavengeBeforeRemark -.RS 4 +.sp +.nf +\f3\-XX:CMSInitiatingOccupancyFraction=20\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:+CMSScavengeBeforeRemark +.br Enables scavenging attempts before the CMS remark step\&. By default, this option is disabled\&. -.RE -.PP -\-XX:CMSTriggerRatio=\fIpercent\fR -.RS 4 -Sets the percentage (0 to 100) of the value specified by -\fB\-XX:MinHeapFreeRatio\fR -that is allocated before a CMS collection cycle commences\&. The default value is set to 80%\&. -.sp +.TP +-XX:CMSTriggerRatio=\fIpercent\fR +.br +Sets the percentage (0 to 100) of the value specified by \f3-XX:MinHeapFreeRatio\fR that is allocated before a CMS collection cycle commences\&. The default value is set to 80%\&. + The following example shows how to set the occupancy fraction to 75%: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:CMSTriggerRatio=75\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:ConcGCThreads=\fIthreads\fR -.RS 4 +.sp +.nf +\f3\-XX:CMSTriggerRatio=75\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:ConcGCThreads=\fIthreads\fR +.br Sets the number of threads used for concurrent GC\&. The default value depends on the number of CPUs available to the JVM\&. -.sp + For example, to set the number of threads for concurrent GC to 2, specify the following option: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:ConcGCThreads=2\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:+DisableExplicitGC -.RS 4 -Enables the option that disables processing of calls to -\fBSystem\&.gc()\fR\&. This option is disabled by default, meaning that calls to -\fBSystem\&.gc()\fR -are processed\&. If processing of calls to -\fBSystem\&.gc()\fR -is disabled, the JVM still performs GC when necessary\&. -.RE -.PP -\-XX:+ExplicitGCInvokesConcurrent -.RS 4 -Enables invoking of concurrent GC by using the -\fBSystem\&.gc()\fR -request\&. This option is disabled by default and can be enabled only together with the -\fB\-XX:+UseConcMarkSweepGC\fR -option\&. -.RE -.PP -\-XX:+ExplicitGCInvokesConcurrentAndUnloadsClasses -.RS 4 -Enables invoking of concurrent GC by using the -\fBSystem\&.gc()\fR -request and unloading of classes during the concurrent GC cycle\&. This option is disabled by default and can be enabled only together with the -\fB\-XX:+UseConcMarkSweepGC\fR -option\&. -.RE -.PP -\-XX:G1HeapRegionSize=\fIsize\fR -.RS 4 -Sets the size of the regions into which the Java heap is subdivided when using the garbage\-first (G1) collector\&. The value can be between 1 MB and 32 MB\&. The default region size is determined ergonomically based on the heap size\&. -.sp +.sp +.nf +\f3\-XX:ConcGCThreads=2\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:+DisableExplicitGC +.br +Enables the option that disables processing of calls to \f3System\&.gc()\fR\&. This option is disabled by default, meaning that calls to \f3System\&.gc()\fR are processed\&. If processing of calls to \f3System\&.gc()\fR is disabled, the JVM still performs GC when necessary\&. +.TP +-XX:+ExplicitGCInvokesConcurrent +.br +Enables invoking of concurrent GC by using the \f3System\&.gc()\fR request\&. This option is disabled by default and can be enabled only together with the \f3-XX:+UseConcMarkSweepGC\fR option\&. +.TP +-XX:+ExplicitGCInvokesConcurrentAndUnloadsClasses +.br +Enables invoking of concurrent GC by using the \f3System\&.gc()\fR request and unloading of classes during the concurrent GC cycle\&. This option is disabled by default and can be enabled only together with the \f3-XX:+UseConcMarkSweepGC\fR option\&. +.TP +-XX:G1HeapRegionSize=\fIsize\fR +.br +Sets the size of the regions into which the Java heap is subdivided when using the garbage-first (G1) collector\&. The value can be between 1 MB and 32 MB\&. The default region size is determined ergonomically based on the heap size\&. + The following example shows how to set the size of the subdivisions to 16 MB: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:G1HeapRegionSize=16m\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:+G1PrintHeapRegions -.RS 4 +.sp +.nf +\f3\-XX:G1HeapRegionSize=16m\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:+G1PrintHeapRegions +.br Enables the printing of information about which regions are allocated and which are reclaimed by the G1 collector\&. By default, this option is disabled\&. -.RE -.PP -\-XX:G1ReservePercent=\fIpercent\fR -.RS 4 +.TP +-XX:G1ReservePercent=\fIpercent\fR +.br Sets the percentage of the heap (0 to 50) that is reserved as a false ceiling to reduce the possibility of promotion failure for the G1 collector\&. By default, this option is set to 10%\&. -.sp + The following example shows how to set the reserved heap to 20%: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:G1ReservePercent=20\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:InitialHeapSize=\fIsize\fR -.RS 4 -Sets the initial size (in bytes) of the memory allocation pool\&. This value must be either 0, or a multiple of 1024 and greater than 1 MB\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. The default value is chosen at runtime based on system configuration\&. For more information, see Garbage Collector Ergonomics at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/gc\-ergonomics\&.html -.sp +.sp +.nf +\f3\-XX:G1ReservePercent=20\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:InitialHeapSize=\fIsize\fR +.br +Sets the initial size (in bytes) of the memory allocation pool\&. This value must be either 0, or a multiple of 1024 and greater than 1 MB\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. The default value is chosen at runtime based on system configuration\&. See the section "Ergonomics" in \fIJava SE HotSpot Virtual Machine Garbage Collection Tuning Guide\fR at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/gctuning/index\&.html\&. + The following examples show how to set the size of allocated memory to 6 MB using various units: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:InitialHeapSize=6291456\fR -\fB\-XX:InitialHeapSize=6144k\fR -\fB\-XX:InitialHeapSize=6m\fR - -.fi -.if n \{\ -.RE -.\} -If you set this option to 0, then the initial size will be set as the sum of the sizes allocated for the old generation and the young generation\&. The size of the heap for the young generation can be set using the -\fB\-XX:NewSize\fR -option\&. -.RE -.PP -\-XX:InitialSurvivorRatio=\fIratio\fR -.RS 4 -Sets the initial survivor space ratio used by the throughput garbage collector (which is enabled by the -\fB\-XX:+UseParallelGC\fR -and/or \-\fBXX:+UseParallelOldGC\fR -options)\&. Adaptive sizing is enabled by default with the throughput garbage collector by using the -\fB\-XX:+UseParallelGC\fR -and -\fB\-XX:+UseParallelOldGC\fR -options, and survivor space is resized according to the application behavior, starting with the initial value\&. If adaptive sizing is disabled (using the -\fB\-XX:\-UseAdaptiveSizePolicy\fR -option), then the -\fB\-XX:SurvivorRatio\fR -option should be used to set the size of the survivor space for the entire execution of the application\&. -.sp +.sp +.nf +\f3\-XX:InitialHeapSize=6291456\fP +.fi +.nf +\f3\-XX:InitialHeapSize=6144k\fP +.fi +.nf +\f3\-XX:InitialHeapSize=6m\fP +.fi +.nf +\f3\fP +.fi +.sp + + +If you set this option to 0, then the initial size will be set as the sum of the sizes allocated for the old generation and the young generation\&. The size of the heap for the young generation can be set using the \f3-XX:NewSize\fR option\&. +.TP +-XX:InitialSurvivorRatio=\fIratio\fR +.br +Sets the initial survivor space ratio used by the throughput garbage collector (which is enabled by the \f3-XX:+UseParallelGC\fR and/or -\f3XX:+UseParallelOldGC\fR options)\&. Adaptive sizing is enabled by default with the throughput garbage collector by using the \f3-XX:+UseParallelGC\fR and \f3-XX:+UseParallelOldGC\fR options, and survivor space is resized according to the application behavior, starting with the initial value\&. If adaptive sizing is disabled (using the \f3-XX:-UseAdaptiveSizePolicy\fR option), then the \f3-XX:SurvivorRatio\fR option should be used to set the size of the survivor space for the entire execution of the application\&. + The following formula can be used to calculate the initial size of survivor space (S) based on the size of the young generation (Y), and the initial survivor space ratio (R): -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBS=Y/(R+2)\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3S=Y/(R+2)\fP +.fi +.nf +\f3\fP +.fi +.sp + + The 2 in the equation denotes two survivor spaces\&. The larger the value specified as the initial survivor space ratio, the smaller the initial survivor space size\&. -.sp + By default, the initial survivor space ratio is set to 8\&. If the default value for the young generation space size is used (2 MB), the initial size of the survivor space will be 0\&.2 MB\&. -.sp + The following example shows how to set the initial survivor space ratio to 4: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:InitialSurvivorRatio=4\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:InitiatingHeapOccupancyPercent=\fIpercent\fR -.RS 4 +.sp +.nf +\f3\-XX:InitialSurvivorRatio=4\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:InitiatingHeapOccupancyPercent=\fIpercent\fR +.br Sets the percentage of the heap occupancy (0 to 100) at which to start a concurrent GC cycle\&. It is used by garbage collectors that trigger a concurrent GC cycle based on the occupancy of the entire heap, not just one of the generations (for example, the G1 garbage collector)\&. -.sp + By default, the initiating value is set to 45%\&. A value of 0 implies nonstop GC cycles\&. The following example shows how to set the initiating heap occupancy to 75%: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:InitiatingHeapOccupancyPercent=75\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:MaxGCPauseMillis=\fItime\fR -.RS 4 +.sp +.nf +\f3\-XX:InitiatingHeapOccupancyPercent=75\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:MaxGCPauseMillis=\fItime\fR +.br Sets a target for the maximum GC pause time (in milliseconds)\&. This is a soft goal, and the JVM will make its best effort to achieve it\&. By default, there is no maximum pause time value\&. -.sp + The following example shows how to set the maximum target pause time to 500 ms: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MaxGCPauseMillis=500\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:MaxHeapSize=\fIsize\fR -.RS 4 -Sets the maximum size (in byes) of the memory allocation pool\&. This value must be a multiple of 1024 and greater than 2 MB\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. The default value is chosen at runtime based on system configuration\&. For server deployments, -\fB\-XX:InitialHeapSize\fR -and -\fB\-XX:MaxHeapSize\fR -are often set to the same value\&. For more information, see Garbage Collector Ergonomics at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/gc\-ergonomics\&.html -.sp +.sp +.nf +\f3\-XX:MaxGCPauseMillis=500\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:MaxHeapSize=\fIsize\fR +.br +Sets the maximum size (in byes) of the memory allocation pool\&. This value must be a multiple of 1024 and greater than 2 MB\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. The default value is chosen at runtime based on system configuration\&. For server deployments, \f3-XX:InitialHeapSize\fR and \f3-XX:MaxHeapSize\fR are often set to the same value\&. See the section "Ergonomics" in \fIJava SE HotSpot Virtual Machine Garbage Collection Tuning Guide\fR at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/vm/gctuning/index\&.html\&. + The following examples show how to set the maximum allowed size of allocated memory to 80 MB using various units: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MaxHeapSize=83886080\fR -\fB\-XX:MaxHeapSize=81920k\fR -\fB\-XX:MaxHeapSize=80m\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3\-XX:MaxHeapSize=83886080\fP +.fi +.nf +\f3\-XX:MaxHeapSize=81920k\fP +.fi +.nf +\f3\-XX:MaxHeapSize=80m\fP +.fi +.nf +\f3\fP +.fi +.sp + + On Oracle Solaris 7 and Oracle Solaris 8 SPARC platforms, the upper limit for this value is approximately 4,000 MB minus overhead amounts\&. On Oracle Solaris 2\&.6 and x86 platforms, the upper limit is approximately 2,000 MB minus overhead amounts\&. On Linux platforms, the upper limit is approximately 2,000 MB minus overhead amounts\&. -.sp -The -\fB\-XX:MaxHeapSize\fR -option is equivalent to -\fB\-Xmx\fR\&. -.RE -.PP -\-XX:MaxHeapFreeRatio=\fIpercent\fR -.RS 4 + +The \f3-XX:MaxHeapSize\fR option is equivalent to \f3-Xmx\fR\&. +.TP +-XX:MaxHeapFreeRatio=\fIpercent\fR +.br Sets the maximum allowed percentage of free heap space (0 to 100) after a GC event\&. If free heap space expands above this value, then the heap will be shrunk\&. By default, this value is set to 70%\&. -.sp + The following example shows how to set the maximum free heap ratio to 75%: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MaxHeapFreeRatio=75\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:MaxMetaspaceSize=\fIsize\fR -.RS 4 +.sp +.nf +\f3\-XX:MaxHeapFreeRatio=75\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:MaxMetaspaceSize=\fIsize\fR +.br Sets the maximum amount of native memory that can be allocated for class metadata\&. By default, the size is not limited\&. The amount of metadata for an application depends on the application itself, other running applications, and the amount of memory available on the system\&. -.sp + The following example shows how to set the maximum class metadata size to 256 MB: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MaxMetaspaceSize=256m\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:MaxNewSize=\fIsize\fR -.RS 4 +.sp +.nf +\f3\-XX:MaxMetaspaceSize=256m\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:MaxNewSize=\fIsize\fR +.br Sets the maximum size (in bytes) of the heap for the young generation (nursery)\&. The default value is set ergonomically\&. -.RE -.PP -\-XX:MaxTenuringThreshold=\fIthreshold\fR -.RS 4 +.TP +-XX:MaxTenuringThreshold=\fIthreshold\fR +.br Sets the maximum tenuring threshold for use in adaptive GC sizing\&. The largest value is 15\&. The default value is 15 for the parallel (throughput) collector, and 6 for the CMS collector\&. -.sp + The following example shows how to set the maximum tenuring threshold to 10: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MaxTenuringThreshold=10\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:MetaspaceSize=\fIsize\fR -.RS 4 +.sp +.nf +\f3\-XX:MaxTenuringThreshold=10\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:MetaspaceSize=\fIsize\fR +.br Sets the size of the allocated class metadata space that will trigger a garbage collection the first time it is exceeded\&. This threshold for a garbage collection is increased or decreased depending on the amount of metadata used\&. The default size depends on the platform\&. -.RE -.PP -\-XX:MinHeapFreeRatio=\fIpercent\fR -.RS 4 +.TP +-XX:MinHeapFreeRatio=\fIpercent\fR +.br Sets the minimum allowed percentage of free heap space (0 to 100) after a GC event\&. If free heap space falls below this value, then the heap will be expanded\&. By default, this value is set to 40%\&. -.sp + The following example shows how to set the minimum free heap ratio to 25%: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:MinHeapFreeRatio=25\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:NewRatio=\fIratio\fR -.RS 4 +.sp +.nf +\f3\-XX:MinHeapFreeRatio=25\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:NewRatio=\fIratio\fR +.br Sets the ratio between young and old generation sizes\&. By default, this option is set to 2\&. The following example shows how to set the young/old ratio to 1: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:NewRatio=1\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:NewSize=\fIsize\fR -.RS 4 -Sets the initial size (in bytes) of the heap for the young generation (nursery)\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. -.sp +.sp +.nf +\f3\-XX:NewRatio=1\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:NewSize=\fIsize\fR +.br +Sets the initial size (in bytes) of the heap for the young generation (nursery)\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. + The young generation region of the heap is used for new objects\&. GC is performed in this region more often than in other regions\&. If the size for the young generation is too low, then a large number of minor GCs will be performed\&. If the size is too high, then only full GCs will be performed, which can take a long time to complete\&. Oracle recommends that you keep the size for the young generation between a half and a quarter of the overall heap size\&. -.sp + The following examples show how to set the initial size of young generation to 256 MB using various units: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:NewSize=256m\fR -\fB\-XX:NewSize=262144k\fR -\fB\-XX:NewSize=268435456\fR - -.fi -.if n \{\ -.RE -.\} -The -\fB\-XX:NewSize\fR -option is equivalent to -\fB\-Xmn\fR\&. -.RE -.PP -\-XX:ParallelGCThreads=\fIthreads\fR -.RS 4 +.sp +.nf +\f3\-XX:NewSize=256m\fP +.fi +.nf +\f3\-XX:NewSize=262144k\fP +.fi +.nf +\f3\-XX:NewSize=268435456\fP +.fi +.nf +\f3\fP +.fi +.sp + + +The \f3-XX:NewSize\fR option is equivalent to \f3-Xmn\fR\&. +.TP +-XX:ParallelGCThreads=\fIthreads\fR +.br Sets the number of threads used for parallel garbage collection in the young and old generations\&. The default value depends on the number of CPUs available to the JVM\&. -.sp + For example, to set the number of threads for parallel GC to 2, specify the following option: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:ParallelGCThreads=2\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:+ParallelRefProcEnabled -.RS 4 +.sp +.nf +\f3\-XX:ParallelGCThreads=2\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:+ParallelRefProcEnabled +.br Enables parallel reference processing\&. By default, this option is disabled\&. -.RE -.PP -\-XX:+PrintAdaptiveSizePolicy -.RS 4 +.TP +-XX:+PrintAdaptiveSizePolicy +.br Enables printing of information about adaptive generation sizing\&. By default, this option is disabled\&. -.RE -.PP -\-XX:+PrintGC -.RS 4 +.TP +-XX:+PrintGC +.br Enables printing of messages at every GC\&. By default, this option is disabled\&. -.RE -.PP -\-XX:+PrintGCApplicationConcurrentTime -.RS 4 +.TP +-XX:+PrintGCApplicationConcurrentTime +.br Enables printing of how much time elapsed since the last pause (for example, a GC pause)\&. By default, this option is disabled\&. -.RE -.PP -\-XX:+PrintGCApplicationStoppedTime -.RS 4 +.TP +-XX:+PrintGCApplicationStoppedTime +.br Enables printing of how much time the pause (for example, a GC pause) lasted\&. By default, this option is disabled\&. -.RE -.PP -\-XX:+PrintGCDateStamps -.RS 4 +.TP +-XX:+PrintGCDateStamps +.br Enables printing of a date stamp at every GC\&. By default, this option is disabled\&. -.RE -.PP -\-XX:+PrintGCDetails -.RS 4 +.TP +-XX:+PrintGCDetails +.br Enables printing of detailed messages at every GC\&. By default, this option is disabled\&. -.RE -.PP -\-XX:+PrintGCTaskTimeStamps -.RS 4 +.TP +-XX:+PrintGCTaskTimeStamps +.br Enables printing of time stamps for every individual GC worker thread task\&. By default, this option is disabled\&. -.RE -.PP -\-XX:+PrintGCTimeStamps -.RS 4 +.TP +-XX:+PrintGCTimeStamps +.br Enables printing of time stamps at every GC\&. By default, this option is disabled\&. -.RE -.PP -\-XX:+PrintStringDeduplicationStatistics -.RS 4 -Prints detailed deduplication statistics\&. By default, this option is disabled\&. See the -\fB\-XX:+UseStringDeduplication\fR -option\&. -.RE -.PP -\-XX:+PrintTenuringDistribution -.RS 4 +.TP +-XX:+PrintStringDeduplicationStatistics +.br +Prints detailed deduplication statistics\&. By default, this option is disabled\&. See the \f3-XX:+UseStringDeduplication\fR option\&. +.TP +-XX:+PrintTenuringDistribution +.br Enables printing of tenuring age information\&. The following is an example of the output: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBDesired survivor size 48286924 bytes, new threshold 10 (max 10)\fR -\fB\- age 1: 28992024 bytes, 28992024 total\fR -\fB\- age 2: 1366864 bytes, 30358888 total\fR -\fB\- age 3: 1425912 bytes, 31784800 total\fR -\fB\&.\&.\&.\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3Desired survivor size 48286924 bytes, new threshold 10 (max 10)\fP +.fi +.nf +\f3\- age 1: 28992024 bytes, 28992024 total\fP +.fi +.nf +\f3\- age 2: 1366864 bytes, 30358888 total\fP +.fi +.nf +\f3\- age 3: 1425912 bytes, 31784800 total\fP +.fi +.nf +\f3\&.\&.\&.\fP +.fi +.nf +\f3\fP +.fi +.sp + + Age 1 objects are the youngest survivors (they were created after the previous scavenge, survived the latest scavenge, and moved from eden to survivor space)\&. Age 2 objects have survived two scavenges (during the second scavenge they were copied from one survivor space to the next)\&. And so on\&. -.sp + In the preceding example, 28 992 024 bytes survived one scavenge and were copied from eden to survivor space, 1 366 864 bytes are occupied by age 2 objects, etc\&. The third value in each row is the cumulative size of objects of age n or less\&. -.sp + By default, this option is disabled\&. -.RE -.PP -\-XX:+ScavengeBeforeFullGC -.RS 4 -Enables GC of the young generation before each full GC\&. This option is enabled by default\&. Oracle recommends that you -\fIdo not\fR -disable it, because scavenging the young generation before a full GC can reduce the number of objects reachable from the old generation space into the young generation space\&. To disable GC of the young generation before each full GC, specify -\fB\-XX:\-ScavengeBeforeFullGC\fR\&. -.RE -.PP -\-XX:SoftRefLRUPolicyMSPerMB=\fItime\fR -.RS 4 -Sets the amount of time (in milliseconds) a softly reachable object is kept active on the heap after the last time it was referenced\&. The default value is one second of lifetime per free megabyte in the heap\&. The -\fB\-XX:SoftRefLRUPolicyMSPerMB\fR -option accepts integer values representing milliseconds per one megabyte of the current heap size (for Java HotSpot Client VM) or the maximum possible heap size (for Java HotSpot Server VM)\&. This difference means that the Client VM tends to flush soft references rather than grow the heap, whereas the Server VM tends to grow the heap rather than flush soft references\&. In the latter case, the value of the -\fB\-Xmx\fR -option has a significant effect on how quickly soft references are garbage collected\&. -.sp +.TP +-XX:+ScavengeBeforeFullGC +.br +Enables GC of the young generation before each full GC\&. This option is enabled by default\&. Oracle recommends that you \fIdo not\fR disable it, because scavenging the young generation before a full GC can reduce the number of objects reachable from the old generation space into the young generation space\&. To disable GC of the young generation before each full GC, specify \f3-XX:-ScavengeBeforeFullGC\fR\&. +.TP +-XX:SoftRefLRUPolicyMSPerMB=\fItime\fR +.br +Sets the amount of time (in milliseconds) a softly reachable object is kept active on the heap after the last time it was referenced\&. The default value is one second of lifetime per free megabyte in the heap\&. The \f3-XX:SoftRefLRUPolicyMSPerMB\fR option accepts integer values representing milliseconds per one megabyte of the current heap size (for Java HotSpot Client VM) or the maximum possible heap size (for Java HotSpot Server VM)\&. This difference means that the Client VM tends to flush soft references rather than grow the heap, whereas the Server VM tends to grow the heap rather than flush soft references\&. In the latter case, the value of the \f3-Xmx\fR option has a significant effect on how quickly soft references are garbage collected\&. + The following example shows how to set the value to 2\&.5 seconds: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:SoftRefLRUPolicyMSPerMB=2500\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:StringDeduplicationAgeThreshold=\fIthreshold\fR -.RS 4 -\fBString\fR -objects reaching the specified age are considered candidates for deduplication\&. An object\*(Aqs age is a measure of how many times it has survived garbage collection\&. This is sometimes referred to as tenuring; see the -\fB\-XX:+PrintTenuringDistribution\fR -option\&. Note that -\fBString\fR -objects that are promoted to an old heap region before this age has been reached are always considered candidates for deduplication\&. The default value for this option is -\fB3\fR\&. See the -\fB\-XX:+UseStringDeduplication\fR -option\&. -.RE -.PP -\-XX:SurvivorRatio=\fIratio\fR -.RS 4 +.sp +.nf +\f3\-XX:SoftRefLRUPolicyMSPerMB=2500\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:StringDeduplicationAgeThreshold=\fIthreshold\fR +.br +\f3String\fR objects reaching the specified age are considered candidates for deduplication\&. An object\&'s age is a measure of how many times it has survived garbage collection\&. This is sometimes referred to as tenuring; see the \f3-XX:+PrintTenuringDistribution\fR option\&. Note that \f3String\fR objects that are promoted to an old heap region before this age has been reached are always considered candidates for deduplication\&. The default value for this option is \f33\fR\&. See the \f3-XX:+UseStringDeduplication\fR option\&. +.TP +-XX:SurvivorRatio=\fIratio\fR +.br Sets the ratio between eden space size and survivor space size\&. By default, this option is set to 8\&. The following example shows how to set the eden/survivor space ratio to 4: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:SurvivorRatio=4\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:TargetSurvivorRatio=\fIpercent\fR -.RS 4 +.sp +.nf +\f3\-XX:SurvivorRatio=4\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:TargetSurvivorRatio=\fIpercent\fR +.br Sets the desired percentage of survivor space (0 to 100) used after young garbage collection\&. By default, this option is set to 50%\&. -.sp + The following example shows how to set the target survivor space ratio to 30%: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:TargetSurvivorRatio=30\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:TLABSize=\fIsize\fR -.RS 4 -Sets the initial size (in bytes) of a thread\-local allocation buffer (TLAB)\&. Append the letter -\fBk\fR -or -\fBK\fR -to indicate kilobytes, -\fBm\fR -or -\fBM\fR -to indicate megabytes, -\fBg\fR -or -\fBG\fR -to indicate gigabytes\&. If this option is set to 0, then the JVM chooses the initial size automatically\&. -.sp +.sp +.nf +\f3\-XX:TargetSurvivorRatio=30\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:TLABSize=\fIsize\fR +.br +Sets the initial size (in bytes) of a thread-local allocation buffer (TLAB)\&. Append the letter \f3k\fR or \f3K\fR to indicate kilobytes, \f3m\fR or \f3M\fR to indicate megabytes, \f3g\fR or \f3G\fR to indicate gigabytes\&. If this option is set to 0, then the JVM chooses the initial size automatically\&. + The following example shows how to set the initial TLAB size to 512 KB: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-XX:TLABSize=512k\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-XX:+UseAdaptiveSizePolicy -.RS 4 -Enables the use of adaptive generation sizing\&. This option is enabled by default\&. To disable adaptive generation sizing, specify -\fB\-XX:\-UseAdaptiveSizePolicy\fR -and set the size of the memory allocation pool explicitly (see the -\fB\-XX:SurvivorRatio\fR -option)\&. -.RE -.PP -\-XX:+UseCMSInitiatingOccupancyOnly -.RS 4 +.sp +.nf +\f3\-XX:TLABSize=512k\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-XX:+UseAdaptiveSizePolicy +.br +Enables the use of adaptive generation sizing\&. This option is enabled by default\&. To disable adaptive generation sizing, specify \f3-XX:-UseAdaptiveSizePolicy\fR and set the size of the memory allocation pool explicitly (see the \f3-XX:SurvivorRatio\fR option)\&. +.TP +-XX:+UseCMSInitiatingOccupancyOnly +.br Enables the use of the occupancy value as the only criterion for initiating the CMS collector\&. By default, this option is disabled and other criteria may be used\&. -.RE -.PP -\-XX:+UseConcMarkSweepGC -.RS 4 -Enables the use of the CMS garbage collector for the old generation\&. Oracle recommends that you use the CMS garbage collector when application latency requirements cannot be met by the throughput (\fB\-XX:+UseParallelGC\fR) garbage collector\&. The G1 garbage collector (\fB\-XX:+UseG1GC\fR) is another alternative\&. -.sp -By default, this option is disabled and the collector is chosen automatically based on the configuration of the machine and type of the JVM\&. When this option is enabled, the -\fB\-XX:+UseParNewGC\fR -option is automatically set and you should not disable it, because the following combination of options has been deprecated in JDK 8: -\fB\-XX:+UseConcMarkSweepGC \-XX:\-UseParNewGC\fR\&. -.RE -.PP -\-XX:+UseG1GC -.RS 4 -Enables the use of the garbage\-first (G1) garbage collector\&. It is a server\-style garbage collector, targeted for multiprocessor machines with a large amount of RAM\&. It meets GC pause time goals with high probability, while maintaining good throughput\&. The G1 collector is recommended for applications requiring large heaps (sizes of around 6 GB or larger) with limited GC latency requirements (stable and predictable pause time below 0\&.5 seconds)\&. -.sp +.TP +-XX:+UseConcMarkSweepGC +.br +Enables the use of the CMS garbage collector for the old generation\&. Oracle recommends that you use the CMS garbage collector when application latency requirements cannot be met by the throughput (\f3-XX:+UseParallelGC\fR) garbage collector\&. The G1 garbage collector (\f3-XX:+UseG1GC\fR) is another alternative\&. + +By default, this option is disabled and the collector is chosen automatically based on the configuration of the machine and type of the JVM\&. When this option is enabled, the \f3-XX:+UseParNewGC\fR option is automatically set and you should not disable it, because the following combination of options has been deprecated in JDK 8: \f3-XX:+UseConcMarkSweepGC -XX:-UseParNewGC\fR\&. +.TP +-XX:+UseG1GC +.br +Enables the use of the garbage-first (G1) garbage collector\&. It is a server-style garbage collector, targeted for multiprocessor machines with a large amount of RAM\&. It meets GC pause time goals with high probability, while maintaining good throughput\&. The G1 collector is recommended for applications requiring large heaps (sizes of around 6 GB or larger) with limited GC latency requirements (stable and predictable pause time below 0\&.5 seconds)\&. + By default, this option is disabled and the collector is chosen automatically based on the configuration of the machine and type of the JVM\&. -.RE -.PP -\-XX:+UseGCOverheadLimit -.RS 4 -Enables the use of a policy that limits the proportion of time spent by the JVM on GC before an -\fBOutOfMemoryError\fR -exception is thrown\&. This option is enabled, by default and the parallel GC will throw an -\fBOutOfMemoryError\fR -if more than 98% of the total time is spent on garbage collection and less than 2% of the heap is recovered\&. When the heap is small, this feature can be used to prevent applications from running for long periods of time with little or no progress\&. To disable this option, specify -\fB\-XX:\-UseGCOverheadLimit\fR\&. -.RE -.PP -\-XX:+UseNUMA -.RS 4 -Enables performance optimization of an application on a machine with nonuniform memory architecture (NUMA) by increasing the application\*(Aqs use of lower latency memory\&. By default, this option is disabled and no optimization for NUMA is made\&. The option is only available when the parallel garbage collector is used (\fB\-XX:+UseParallelGC\fR)\&. -.RE -.PP -\-XX:+UseParallelGC -.RS 4 +.TP +-XX:+UseGCOverheadLimit +.br +Enables the use of a policy that limits the proportion of time spent by the JVM on GC before an \f3OutOfMemoryError\fR exception is thrown\&. This option is enabled, by default and the parallel GC will throw an \f3OutOfMemoryError\fR if more than 98% of the total time is spent on garbage collection and less than 2% of the heap is recovered\&. When the heap is small, this feature can be used to prevent applications from running for long periods of time with little or no progress\&. To disable this option, specify \f3-XX:-UseGCOverheadLimit\fR\&. +.TP +-XX:+UseNUMA +.br +Enables performance optimization of an application on a machine with nonuniform memory architecture (NUMA) by increasing the application\&'s use of lower latency memory\&. By default, this option is disabled and no optimization for NUMA is made\&. The option is only available when the parallel garbage collector is used (\f3-XX:+UseParallelGC\fR)\&. +.TP +-XX:+UseParallelGC +.br Enables the use of the parallel scavenge garbage collector (also known as the throughput collector) to improve the performance of your application by leveraging multiple processors\&. -.sp -By default, this option is disabled and the collector is chosen automatically based on the configuration of the machine and type of the JVM\&. If it is enabled, then the -\fB\-XX:+UseParallelOldGC\fR -option is automatically enabled, unless you explicitly disable it\&. -.RE -.PP -\-XX:+UseParallelOldGC -.RS 4 -Enables the use of the parallel garbage collector for full GCs\&. By default, this option is disabled\&. Enabling it automatically enables the -\fB\-XX:+UseParallelGC\fR -option\&. -.RE -.PP -\-XX:+UseParNewGC -.RS 4 -Enables the use of parallel threads for collection in the young generation\&. By default, this option is disabled\&. It is automatically enabled when you set the -\fB\-XX:+UseConcMarkSweepGC\fR -option\&. Using the -\fB\-XX:+UseParNewGC\fR -option without the -\fB\-XX:+UseConcMarkSweepGC\fR -option was deprecated in JDK 8\&. -.RE -.PP -\-XX:+UseSerialGC -.RS 4 + +By default, this option is disabled and the collector is chosen automatically based on the configuration of the machine and type of the JVM\&. If it is enabled, then the \f3-XX:+UseParallelOldGC\fR option is automatically enabled, unless you explicitly disable it\&. +.TP +-XX:+UseParallelOldGC +.br +Enables the use of the parallel garbage collector for full GCs\&. By default, this option is disabled\&. Enabling it automatically enables the \f3-XX:+UseParallelGC\fR option\&. +.TP +-XX:+UseParNewGC +.br +Enables the use of parallel threads for collection in the young generation\&. By default, this option is disabled\&. It is automatically enabled when you set the \f3-XX:+UseConcMarkSweepGC\fR option\&. Using the \f3-XX:+UseParNewGC\fR option without the \f3-XX:+UseConcMarkSweepGC\fR option was deprecated in JDK 8\&. +.TP +-XX:+UseSerialGC +.br Enables the use of the serial garbage collector\&. This is generally the best choice for small and simple applications that do not require any special functionality from garbage collection\&. By default, this option is disabled and the collector is chosen automatically based on the configuration of the machine and type of the JVM\&. -.RE -.PP -\-XX:+UseStringDeduplication -.RS 4 -Enables string deduplication\&. By default, this option is disabled\&. To use this option, you must enable the garbage\-first (G1) garbage collector\&. See the -\fB\-XX:+UseG1GC\fR -option\&. -.sp -\fIString deduplication\fR -reduces the memory footprint of -\fBString\fR -objects on the Java heap by taking advantage of the fact that many -\fBString\fR -objects are identical\&. Instead of each -\fBString\fR -object pointing to its own character array, identical -\fBString\fR -objects can point to and share the same character array\&. -.RE -.PP -\-XX:+UseTLAB -.RS 4 -Enables the use of thread\-local allocation blocks (TLABs) in the young generation space\&. This option is enabled by default\&. To disable the use of TLABs, specify -\fB\-XX:\-UseTLAB\fR\&. -.RE -.SS "Deprecated and Removed Options" -.PP +.TP +-XX:+UseSHM +.br +On Linux, enables the JVM to use shared memory to setup large pages\&. + +For more information, see Large Pages\&. +.TP +-XX:+UseStringDeduplication +.br +Enables string deduplication\&. By default, this option is disabled\&. To use this option, you must enable the garbage-first (G1) garbage collector\&. See the \f3-XX:+UseG1GC\fR option\&. + +\fIString deduplication\fR reduces the memory footprint of \f3String\fR objects on the Java heap by taking advantage of the fact that many \f3String\fR objects are identical\&. Instead of each \f3String\fR object pointing to its own character array, identical \f3String\fR objects can point to and share the same character array\&. +.TP +-XX:+UseTLAB +.br +Enables the use of thread-local allocation blocks (TLABs) in the young generation space\&. This option is enabled by default\&. To disable the use of TLABs, specify \f3-XX:-UseTLAB\fR\&. +.SS DEPRECATED\ AND\ REMOVED\ OPTIONS These options were included in the previous release, but have since been considered unnecessary\&. -.PP -\-Xincgc -.RS 4 +.TP +-Xincgc +.br Enables incremental garbage collection\&. This option was deprecated in JDK 8 with no replacement\&. -.RE -.PP -\-Xrun\fIlibname\fR -.RS 4 -Loads the specified debugging/profiling library\&. This option was superseded by the -\fB\-agentlib\fR -option\&. -.RE -.PP -\-XX:CMSIncrementalDutyCycle=\fIpercent\fR -.RS 4 -Sets the percentage of time (0 to 100) between minor collections that the concurrent collector is allowed to run\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the -\fB\-XX:+CMSIncrementalMode\fR -option\&. -.RE -.PP -\-XX:CMSIncrementalDutyCycleMin=\fIpercent\fR -.RS 4 -Sets the percentage of time (0 to 100) between minor collections that is the lower bound for the duty cycle when -\fB\-XX:+CMSIncrementalPacing\fR -is enabled\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the -\fB\-XX:+CMSIncrementalMode\fR -option\&. -.RE -.PP -\-XX:+CMSIncrementalMode -.RS 4 -Enables the incremental mode for the CMS collector\&. This option was deprecated in JDK 8 with no replacement, along with other options that start with -\fBCMSIncremental\fR\&. -.RE -.PP -\-XX:CMSIncrementalOffset=\fIpercent\fR -.RS 4 -Sets the percentage of time (0 to 100) by which the incremental mode duty cycle is shifted to the right within the period between minor collections\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the -\fB\-XX:+CMSIncrementalMode\fR -option\&. -.RE -.PP -\-XX:+CMSIncrementalPacing -.RS 4 -Enables automatic adjustment of the incremental mode duty cycle based on statistics collected while the JVM is running\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the -\fB\-XX:+CMSIncrementalMode\fR -option\&. -.RE -.PP -\-XX:CMSIncrementalSafetyFactor=\fIpercent\fR -.RS 4 -Sets the percentage of time (0 to 100) used to add conservatism when computing the duty cycle\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the -\fB\-XX:+CMSIncrementalMode\fR -option\&. -.RE -.PP -\-XX:CMSInitiatingPermOccupancyFraction=\fIpercent\fR -.RS 4 +.TP +-Xrun\fIlibname\fR +.br +Loads the specified debugging/profiling library\&. This option was superseded by the \f3-agentlib\fR option\&. +.TP +-XX:CMSIncrementalDutyCycle=\fIpercent\fR +.br +Sets the percentage of time (0 to 100) between minor collections that the concurrent collector is allowed to run\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the \f3-XX:+CMSIncrementalMode\fR option\&. +.TP +-XX:CMSIncrementalDutyCycleMin=\fIpercent\fR +.br +Sets the percentage of time (0 to 100) between minor collections that is the lower bound for the duty cycle when \f3-XX:+CMSIncrementalPacing\fR is enabled\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the \f3-XX:+CMSIncrementalMode\fR option\&. +.TP +-XX:+CMSIncrementalMode +.br +Enables the incremental mode for the CMS collector\&. This option was deprecated in JDK 8 with no replacement, along with other options that start with \f3CMSIncremental\fR\&. +.TP +-XX:CMSIncrementalOffset=\fIpercent\fR +.br +Sets the percentage of time (0 to 100) by which the incremental mode duty cycle is shifted to the right within the period between minor collections\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the \f3-XX:+CMSIncrementalMode\fR option\&. +.TP +-XX:+CMSIncrementalPacing +.br +Enables automatic adjustment of the incremental mode duty cycle based on statistics collected while the JVM is running\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the \f3-XX:+CMSIncrementalMode\fR option\&. +.TP +-XX:CMSIncrementalSafetyFactor=\fIpercent\fR +.br +Sets the percentage of time (0 to 100) used to add conservatism when computing the duty cycle\&. This option was deprecated in JDK 8 with no replacement, following the deprecation of the \f3-XX:+CMSIncrementalMode\fR option\&. +.TP +-XX:CMSInitiatingPermOccupancyFraction=\fIpercent\fR +.br Sets the percentage of the permanent generation occupancy (0 to 100) at which to start a GC\&. This option was deprecated in JDK 8 with no replacement\&. -.RE +.TP +-XX:MaxPermSize=\fIsize\fR +.br +Sets the maximum permanent generation space size (in bytes)\&. This option was deprecated in JDK 8, and superseded by the \f3-XX:MaxMetaspaceSize\fR option\&. +.TP +-XX:PermSize=\fIsize\fR +.br +Sets the space (in bytes) allocated to the permanent generation that triggers a garbage collection if it is exceeded\&. This option was deprecated un JDK 8, and superseded by the \f3-XX:MetaspaceSize\fR option\&. +.TP +-XX:+UseSplitVerifier +.br +Enables splitting of the verification process\&. By default, this option was enabled in the previous releases, and verification was split into two phases: type referencing (performed by the compiler) and type checking (performed by the JVM runtime)\&. This option was deprecated in JDK 8, and verification is now split by default without a way to disable it\&. +.TP +-XX:+UseStringCache +.br +Enables caching of commonly allocated strings\&. This option was removed from JDK 8 with no replacement\&. +.SH PERFORMANCE\ TUNING\ EXAMPLES +The following examples show how to use experimental tuning flags to either optimize throughput or to provide lower response time\&. .PP -\-XX:MaxPermSize=\fIsize\fR -.RS 4 -Sets the maximum permanent generation space size (in bytes)\&. This option was deprecated in JDK 8, and superseded by the -\fB\-XX:MaxMetaspaceSize\fR -option\&. -.RE +\f3Example 1 Tuning for Higher Throughput\fR +.sp +.nf +\f3java \-d64 \-server \-XX:+AggressiveOpts \-XX:+UseLargePages \-Xmn10g \-Xms26g \-Xmx26g\fP +.fi +.nf +\f3\fP +.fi +.sp +\f3Example 2 Tuning for Lower Response Time\fR +.sp +.nf +\f3java \-d64 \-XX:+UseG1GC \-Xms26g Xmx26g \-XX:MaxGCPauseMillis=500 \-XX:+PrintGCTimeStamp\fP +.fi +.nf +\f3\fP +.fi +.sp +.SH LARGE\ PAGES +Also known as huge pages, large pages are memory pages that are significantly larger than the standard memory page size (which varies depending on the processor and operating system)\&. Large pages optimize processor Translation-Lookaside Buffers\&. +.PP +A Translation-Lookaside Buffer (TLB) is a page translation cache that holds the most-recently used virtual-to-physical address translations\&. TLB is a scarce system resource\&. A TLB miss can be costly as the processor must then read from the hierarchical page table, which may require multiple memory accesses\&. By using a larger memory page size, a single TLB entry can represent a larger memory range\&. There will be less pressure on TLB, and memory-intensive applications may have better performance\&. +.PP +However, large pages page memory can negatively affect system performance\&. For example, when a large mount of memory is pinned by an application, it may create a shortage of regular memory and cause excessive paging in other applications and slow down the entire system\&. Also, a system that has been up for a long time could produce excessive fragmentation, which could make it impossible to reserve enough large page memory\&. When this happens, either the OS or JVM reverts to using regular pages\&. +.SS LARGE\ PAGES\ SUPPORT +Solaris and Linux support large pages\&. +.PP +Solaris 9 and later include Multiple Page Size Support (MPSS); no additional configuration is necessary\&. See http://www\&.oracle\&.com/technetwork/server-storage/solaris10/overview/solaris9-features-scalability-135663\&.html\&. +.PP +The 2\&.6 kernel supports large pages\&. Some vendors have backported the code to their 2\&.4-based releases\&. To check if your system can support large page memory, try the following: +.sp +.nf +\f3# cat /proc/meminfo | grep Huge\fP +.fi +.nf +\f3HugePages_Total: 0\fP +.fi +.nf +\f3HugePages_Free: 0\fP +.fi +.nf +\f3Hugepagesize: 2048 kB\fP +.fi +.nf +\f3\fP +.fi +.sp +If the output shows the three "Huge" variables, then your system can support large page memory but it needs to be configured\&. If the command prints nothing, then your system does not support large pages\&. To configure the system to use large page memory, login as \f3root\fR, and then follow these steps: +.TP 0.4i +1\&. +If you are using the option \f3-XX:+UseSHM\fR (instead of \f3-XX:+UseHugeTLBFS\fR), then increase the \f3SHMMAX\fR value\&. It must be larger than the Java heap size\&. On a system with 4 GB of physical RAM (or less), the following will make all the memory sharable: +.sp +.nf +\f3# echo 4294967295 > /proc/sys/kernel/shmmax\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP 0.4i +2\&. +If you are using the option \f3-XX:+UseSHM\fR or \f3-XX:+UseHugeTLBFS\fR, then specify the number of large pages\&. In the following example, 3 GB of a 4 GB system are reserved for large pages (assuming a large page size of 2048kB, then 3 GB = 3 * 1024 MB = 3072 MB = 3072 * 1024 kB = 3145728 kB and 3145728 kB / 2048 kB = 1536): +.sp +.nf +\f3# echo 1536 > /proc/sys/vm/nr_hugepages\fP +.fi +.nf +\f3\fP +.fi +.sp + .PP -\-XX:PermSize=\fIsize\fR -.RS 4 -Sets the space (in bytes) allocated to the permanent generation that triggers a garbage collection if it is exceeded\&. This option was deprecated un JDK 8, and superseded by the -\fB\-XX:MetaspaceSize\fR -option\&. -.RE +Note .PP -\-XX:+UseSplitVerifier -.RS 4 -Enables splitting of the verification process\&. By default, this option was enabled in the previous releases, and verification was split into two phases: type referencing (performed by the compiler) and type checking (performed by the JVM runtime)\&. This option was deprecated in JDK 8, and verification is now split by default without a way to disable it\&. -.RE +Note that the values contained in \f3/proc\fR will reset after you reboot your system, so may want to set them in an initialization script (for example, \f3rc\&.local\fR or \f3sysctl\&.conf\fR)\&. .PP -\-XX:+UseStringCache -.RS 4 -Enables caching of commonly allocated strings\&. This option was removed from JDK 8 with no replacement\&. -.RE -.SH "PERFORMANCE TUNING EXAMPLES" +If you configure (or resize) the OS kernel parameters \f3/proc/sys/kernel/shmmax\fR or \f3/proc/sys/vm/nr_hugepages\fR, Java processes may allocate large pages for areas in addition to the Java heap\&. These steps can allocate large pages for the following areas: .PP -The following examples show how to use experimental tuning flags to either optimize throughput or to provide lower response time\&. +Java heap .PP -\fBExample 1\fR -.br -Tuning for Higher Throughput -.RS 4 -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjava \-d64 \-server \-XX:+AggressiveOpts \-XX:+UseLargePages \-Xmn10g \-Xms26g \-Xmx26g\fR - -.fi -.if n \{\ -.RE -.\} -.RE +Permanent generation .PP -\fBExample 2\fR -.br -Tuning for Lower Response Time -.RS 4 -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjava \-d64 \-XX:+UseG1GC \-Xms26g Xmx26g \-XX:MaxGCPauseMillis=500 \-XX:+PrintGCTimeStamp\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.SH "EXIT STATUS" +Code cache .PP -The following exit values are typically returned by the launcher when the launcher is called with the wrong arguments, serious errors, or exceptions thrown by the JVM\&. However, a Java application may choose to return any value by using the API call -\fBSystem\&.exit(exitValue)\fR\&. The values are: -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -\fB0\fR: Successful completion -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -\fB>0\fR: An error occurred -.RE -.SH "SEE ALSO" -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +The marking bitmap data structure for the parallel GC +.PP +Consequently, if you configure the \f3nr_hugepages\fR parameter to the size of the Java heap, then the JVM can fail in allocating the permanent generation and code cache areas on large pages because these areas are quite large in size\&. +.SH EXIT\ STATUS +The following exit values are typically returned by the launcher when the launcher is called with the wrong arguments, serious errors, or exceptions thrown by the JVM\&. However, a Java application may choose to return any value by using the API call \f3System\&.exit(exitValue)\fR\&. The values are: +.TP 0.2i +\(bu +\f30\fR: Successful completion +.TP 0.2i +\(bu +\f3>0\fR: An error occurred +.SH SEE\ ALSO +.TP 0.2i +\(bu javac(1) -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu jdb(1) -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu javah(1) -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu jar(1) -.RE -.br -'pl 8.5i -'bp +.TP 0.2i +\(bu +jstat(1) +.RE +.br +'pl 8.5i +'bp diff --git a/src/bsd/doc/man/javac.1 b/src/bsd/doc/man/javac.1 index a3d55e275..5cc8c18e9 100644 --- a/src/bsd/doc/man/javac.1 +++ b/src/bsd/doc/man/javac.1 @@ -1,2116 +1,1370 @@ '\" t -.\" Copyright (c) 1994, 2014, Oracle and/or its affiliates. All rights reserved. -.\" -.\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. -.\" -.\" This code is free software; you can redistribute it and/or modify it -.\" under the terms of the GNU General Public License version 2 only, as -.\" published by the Free Software Foundation. -.\" -.\" This code is distributed in the hope that it will be useful, but WITHOUT -.\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or -.\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -.\" version 2 for more details (a copy is included in the LICENSE file that -.\" accompanied this code). -.\" -.\" You should have received a copy of the GNU General Public License version -.\" 2 along with this work; if not, write to the Free Software Foundation, -.\" Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. -.\" -.\" Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA -.\" or visit www.oracle.com if you need additional information or have any -.\" questions. -.\" -.\" Title: javac -.\" Language: English -.\" Date: 8 August 2014 -.\" SectDesc: Basic Tools -.\" Software: JDK 8 -.\" Arch: generic -.\" Part Number: E38207-03 +.\" Copyright (c) 1994, 2015, Oracle and/or its affiliates. All rights reserved. +.\" +.\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. +.\" +.\" This code is free software; you can redistribute it and/or modify it +.\" under the terms of the GNU General Public License version 2 only, as +.\" published by the Free Software Foundation. +.\" +.\" This code is distributed in the hope that it will be useful, but WITHOUT +.\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or +.\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +.\" version 2 for more details (a copy is included in the LICENSE file that +.\" accompanied this code). +.\" +.\" You should have received a copy of the GNU General Public License version +.\" 2 along with this work; if not, write to the Free Software Foundation, +.\" Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. +.\" +.\" Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA +.\" or visit www.oracle.com if you need additional information or have any +.\" questions. +.\" +.\" Arch: generic +.\" Software: JDK 8 +.\" Date: 03 March 2015 +.\" SectDesc: Basic Tools +.\" Title: javac.1 .\" .if n .pl 99999 -.TH "javac" "1" "8 August 2014" "JDK 8" "Basic Tools" -.\" ----------------------------------------------------------------- -.\" * Define some portability stuff -.\" ----------------------------------------------------------------- -.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -.\" http://bugs.debian.org/507673 -.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html -.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -.ie \n(.g .ds Aq \(aq -.el .ds Aq ' -.\" ----------------------------------------------------------------- -.\" * set default formatting -.\" ----------------------------------------------------------------- -.\" disable hyphenation -.nh -.\" disable justification (adjust text to left margin only) -.ad l -.\" ----------------------------------------------------------------- -.\" * MAIN CONTENT STARTS HERE * -.\" ----------------------------------------------------------------- -.SH "NAME" +.TH javac 1 "03 March 2015" "JDK 8" "Basic Tools" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- + +.SH NAME javac \- Reads Java class and interface definitions and compiles them into bytecode and class files\&. -.SH "SYNOPSIS" -.sp -.if n \{\ -.RS 4 -.\} -.nf +.SH SYNOPSIS +.sp +.nf + \fBjavac\fR [ \fIoptions\fR ] [ \fIsourcefiles\fR ] [ \fIclasses\fR] [ \fI@argfiles\fR ] -.fi -.if n \{\ -.RE -.\} -.PP +.fi +.sp Arguments can be in any order: -.PP +.TP \fIoptions\fR -.RS 4 -Command\-line options\&. See Options\&. -.RE -.PP +Command-line options\&. See Options\&. +.TP \fIsourcefiles\fR -.RS 4 -One or more source files to be compiled (such as -\fBMyClass\&.java\fR)\&. -.RE -.PP +One or more source files to be compiled (such as \f3MyClass\&.java\fR)\&. +.TP \fIclasses\fR -.RS 4 -One or more classes to be processed for annotations (such as -\fBMyPackage\&.MyClass\fR)\&. -.RE -.PP +One or more classes to be processed for annotations (such as \f3MyPackage\&.MyClass\fR)\&. +.TP \fI@argfiles\fR -.RS 4 -One or more files that list options and source files\&. The -\fB\-J\fR -options are not allowed in these files\&. See Command\-Line Argument Files\&. -.RE -.SH "DESCRIPTION" -.PP -The -\fBjavac\fR -command reads class and interface definitions, written in the Java programming language, and compiles them into bytecode class files\&. The -\fBjavac\fR -command can also process annotations in Java source files and classes\&. +One or more files that list options and source files\&. The \f3-J\fR options are not allowed in these files\&. See Command-Line Argument Files\&. +.SH DESCRIPTION +The \f3javac\fR command reads class and interface definitions, written in the Java programming language, and compiles them into bytecode class files\&. The \f3javac\fR command can also process annotations in Java source files and classes\&. .PP -There are two ways to pass source code file names to -\fBjavac\fR\&. -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +There are two ways to pass source code file names to \f3javac\fR\&. +.TP 0.2i +\(bu For a small number of source files, list the file names on the command line\&. -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -For a large number of source files, list the file names in a file that is separated by blanks or line breaks\&. Use the list file name preceded by an at sign (@) with the -\fBjavac\fR -command\&. -.RE +.TP 0.2i +\(bu +For a large number of source files, list the file names in a file that is separated by blanks or line breaks\&. Use the list file name preceded by an at sign (@) with the \f3javac\fR command\&. .PP -Source code file names must have \&.java suffixes, class file names must have \&.class suffixes, and both source and class files must have root names that identify the class\&. For example, a class called -\fBMyClass\fR -would be written in a source file called -\fBMyClass\&.java\fR -and compiled into a bytecode class file called -\fBMyClass\&.class\fR\&. +Source code file names must have \&.java suffixes, class file names must have \&.class suffixes, and both source and class files must have root names that identify the class\&. For example, a class called \f3MyClass\fR would be written in a source file called \f3MyClass\&.java\fR and compiled into a bytecode class file called \f3MyClass\&.class\fR\&. .PP -Inner class definitions produce additional class files\&. These class files have names that combine the inner and outer class names, such as -\fBMyClass$MyInnerClass\&.class\fR\&. +Inner class definitions produce additional class files\&. These class files have names that combine the inner and outer class names, such as \f3MyClass$MyInnerClass\&.class\fR\&. .PP -Arrange source files in a directory tree that reflects their package tree\&. For example, if all of your source files are in -\fB/workspace\fR, then put the source code for -\fBcom\&.mysoft\&.mypack\&.MyClass\fR -in -\fB/workspace/com/mysoft/mypack/MyClass\&.java\fR\&. +Arrange source files in a directory tree that reflects their package tree\&. For example, if all of your source files are in \f3/workspace\fR, then put the source code for \f3com\&.mysoft\&.mypack\&.MyClass\fR in \f3/workspace/com/mysoft/mypack/MyClass\&.java\fR\&. .PP -By default, the compiler puts each class file in the same directory as its source file\&. You can specify a separate destination directory with the -\fB\-d\fR -option\&. -.SH "OPTIONS" -.PP -The compiler has a set of standard options that are supported on the current development environment\&. An additional set of nonstandard options are specific to the current virtual machine and compiler implementations and are subject to change in the future\&. Nonstandard options begin with the -\fB\-X\fR -option\&. -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -See also Cross\-Compilation Options -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +By default, the compiler puts each class file in the same directory as its source file\&. You can specify a separate destination directory with the \f3-d\fR option\&. +.SH OPTIONS +The compiler has a set of standard options that are supported on the current development environment\&. An additional set of nonstandard options are specific to the current virtual machine and compiler implementations and are subject to change in the future\&. Nonstandard options begin with the \f3-X\fR option\&. +.TP 0.2i +\(bu +See also Cross-Compilation Options +.TP 0.2i +\(bu See also Nonstandard Options -.RE -.SS "Standard Options" -.PP -\-A\fIkey\fR[\fI=value\fR] -.RS 4 -Specifies options to pass to annotation processors\&. These options are not interpreted by -\fBjavac\fR -directly, but are made available for use by individual processors\&. The -\fBkey\fR -value should be one or more identifiers separated by a dot (\&.)\&. -.RE -.PP -\-cp \fIpath\fR or \-classpath \fIpath\fR -.RS 4 -Specifies where to find user class files, and (optionally) annotation processors and source files\&. This class path overrides the user class path in the -\fBCLASSPATH\fR -environment variable\&. If neither -\fBCLASSPATH\fR, -\fB\-cp\fR -nor -\fB\-classpath\fR -is specified, then the user -\fIclass path\fR -is the current directory\&. See Setting the Class Path \&. -.sp -If the -\fB\-sourcepath\fR -option is not specified, then the user class path is also searched for source files\&. -.sp -If the -\fB\-processorpath\fR -option is not specified, then the class path is also searched for annotation processors\&. -.RE -.PP -\-Djava\&.ext\&.dirs=\fIdirectories\fR -.RS 4 +.SS STANDARD\ OPTIONS +.TP +-A\fIkey\fR[\fI=value\fR] +.br +Specifies options to pass to annotation processors\&. These options are not interpreted by \f3javac\fR directly, but are made available for use by individual processors\&. The \f3key\fR value should be one or more identifiers separated by a dot (\&.)\&. +.TP +-cp \fIpath\fR or -classpath \fIpath\fR +.br +Specifies where to find user class files, and (optionally) annotation processors and source files\&. This class path overrides the user class path in the \f3CLASSPATH\fR environment variable\&. If neither \f3CLASSPATH\fR, \f3-cp\fR nor \f3-classpath\fR is specified, then the user \fIclass path\fR is the current directory\&. See Setting the Class Path\&. + +If the \f3-sourcepath\fR option is not specified, then the user class path is also searched for source files\&. + +If the \f3-processorpath\fR option is not specified, then the class path is also searched for annotation processors\&. +.TP +-Djava\&.ext\&.dirs=\fIdirectories\fR +.br Overrides the location of installed extensions\&. -.RE -.PP -\-Djava\&.endorsed\&.dirs=\fIdirectories\fR -.RS 4 +.TP +-Djava\&.endorsed\&.dirs=\fIdirectories\fR +.br Overrides the location of the endorsed standards path\&. -.RE -.PP -\-d \fIdirectory\fR -.RS 4 -Sets the destination directory for class files\&. The directory must already exist because -\fBjavac\fR -does not create it\&. If a class is part of a package, then -\fBjavac\fR -puts the class file in a subdirectory that reflects the package name and creates directories as needed\&. -.sp -If you specify -\fB\-d\fR -\fB/home/myclasses\fR -and the class is called -\fBcom\&.mypackage\&.MyClass\fR, then the class file is -\fB/home/myclasses/com/mypackage/MyClass\&.class\fR\&. -.sp -If the -\fI\-d\fR -option is not specified, then -\fBjavac\fR -puts each class file in the same directory as the source file from which it was generated\&. -.sp -\fBNote:\fR -The directory specified by the -\fI\-d\fR -option is not automatically added to your user class path\&. -.RE -.PP -\-deprecation -.RS 4 -Shows a description of each use or override of a deprecated member or class\&. Without the -\fB\-deprecation\fR -option, -\fBjavac\fR -shows a summary of the source files that use or override deprecated members or classes\&. The -\fB\-deprecation\fR -option is shorthand for -\fB\-Xlint:deprecation\fR\&. -.RE -.PP -\-encoding \fIencoding\fR -.RS 4 -Sets the source file encoding name, such as EUC\-JP and UTF\-8\&. If the -\fB\-encoding\fR -option is not specified, then the platform default converter is used\&. -.RE -.PP -\-endorseddirs \fIdirectories\fR -.RS 4 +.TP +-d \fIdirectory\fR +.br +Sets the destination directory for class files\&. The directory must already exist because \f3javac\fR does not create it\&. If a class is part of a package, then \f3javac\fR puts the class file in a subdirectory that reflects the package name and creates directories as needed\&. + +If you specify \f3-d\fR\f3/home/myclasses\fR and the class is called \f3com\&.mypackage\&.MyClass\fR, then the class file is \f3/home/myclasses/com/mypackage/MyClass\&.class\fR\&. + +If the \fI-d\fR option is not specified, then \f3javac\fR puts each class file in the same directory as the source file from which it was generated\&. + +\fINote:\fR The directory specified by the \fI-d\fR option is not automatically added to your user class path\&. +.TP +-deprecation +.br +Shows a description of each use or override of a deprecated member or class\&. Without the \f3-deprecation\fR option, \f3javac\fR shows a summary of the source files that use or override deprecated members or classes\&. The \f3-deprecation\fR option is shorthand for \f3-Xlint:deprecation\fR\&. +.TP +-encoding \fIencoding\fR +.br +Sets the source file encoding name, such as EUC-JP and UTF-8\&. If the \f3-encoding\fR option is not specified, then the platform default converter is used\&. +.TP +-endorseddirs \fIdirectories\fR +.br Overrides the location of the endorsed standards path\&. -.RE -.PP -\-extdirs \fIdirectories\fR -.RS 4 -Overrides the location of the -\fBext\fR -directory\&. The directories variable is a colon\-separated list of directories\&. Each JAR file in the specified directories is searched for class files\&. All JAR files found become part of the class path\&. -.sp -If you are cross\-compiling (compiling classes against bootstrap and extension classes of a different Java platform implementation), then this option specifies the directories that contain the extension classes\&. See Cross\-Compilation Options for more information\&. -.RE -.PP -\-g -.RS 4 +.TP +-extdirs \fIdirectories\fR +.br +Overrides the location of the \f3ext\fR directory\&. The directories variable is a colon-separated list of directories\&. Each JAR file in the specified directories is searched for class files\&. All JAR files found become part of the class path\&. + +If you are cross-compiling (compiling classes against bootstrap and extension classes of a different Java platform implementation), then this option specifies the directories that contain the extension classes\&. See Cross-Compilation Options for more information\&. +.TP +-g +.br Generates all debugging information, including local variables\&. By default, only line number and source file information is generated\&. -.RE -.PP -\-g:none -.RS 4 +.TP +-g:none +.br Does not generate any debugging information\&. -.RE -.PP -\-g:[\fIkeyword list\fR] -.RS 4 +.TP +-g:[\fIkeyword list\fR] +.br Generates only some kinds of debugging information, specified by a comma separated list of keywords\&. Valid keywords are: -.PP +.RS +.TP source -.RS 4 Source file debugging information\&. -.RE -.PP +.TP lines -.RS 4 Line number debugging information\&. -.RE -.PP +.TP vars -.RS 4 Local variable debugging information\&. -.RE -.RE -.PP -\-help -.RS 4 +.RE + +.TP +-help +.br Prints a synopsis of standard options\&. -.RE -.PP -\-implicit:[\fIclass, none\fR] -.RS 4 -Controls the generation of class files for implicitly loaded source files\&. To automatically generate class files, use -\fB\-implicit:class\fR\&. To suppress class file generation, use -\fB\-implicit:none\fR\&. If this option is not specified, then the default is to automatically generate class files\&. In this case, the compiler issues a warning if any such class files are generated when also doing annotation processing\&. The warning is not issued when the -\fB\-implicit\fR -option is set explicitly\&. See Searching for Types\&. -.RE -.PP -\-J\fIoption\fR -.RS 4 -Passes -\fBoption\fR -to the Java Virtual Machine (JVM), where option is one of the options described on the reference page for the Java launcher\&. For example, -\fB\-J\-Xms48m\fR -sets the startup memory to 48 MB\&. See -java(1)\&. -.sp -\fBNote:\fR -The -\fICLASSPATH\fR, -\fB\-classpath\fR, -\fB\-bootclasspath\fR, and -\fB\-extdirs\fR -options do not specify the classes used to run -\fBjavac\fR\&. Trying to customize the compiler implementation with these options and variables is risky and often does not accomplish what you want\&. If you must customize the complier implementation, then use the -\fB\-J\fR -option to pass options through to the underlying Java launcher\&. -.RE -.PP -\-nowarn -.RS 4 -Disables warning messages\&. This option operates the same as the -\fB\-Xlint:none\fR -option\&. -.RE -.PP -\-parameters -.RS 4 -Stores formal parameter names of constructors and methods in the generated class file so that the method -\fBjava\&.lang\&.reflect\&.Executable\&.getParameters\fR -from the Reflection API can retrieve them\&. -.RE -.PP -\-proc: [\fInone\fR, \fIonly\fR] -.RS 4 -Controls whether annotation processing and compilation are done\&. -\fB\-proc:none\fR -means that compilation takes place without annotation processing\&. -\fB\-proc:only\fR -means that only annotation processing is done, without any subsequent compilation\&. -.RE -.PP -\-processor \fIclass1\fR [,\fIclass2\fR,\fIclass3\fR\&.\&.\&.] -.RS 4 +.TP +-implicit:[\fIclass, none\fR] +.br +Controls the generation of class files for implicitly loaded source files\&. To automatically generate class files, use \f3-implicit:class\fR\&. To suppress class file generation, use \f3-implicit:none\fR\&. If this option is not specified, then the default is to automatically generate class files\&. In this case, the compiler issues a warning if any such class files are generated when also doing annotation processing\&. The warning is not issued when the \f3-implicit\fR option is set explicitly\&. See Searching for Types\&. +.TP +-J\fIoption\fR +.br +Passes \f3option\fR to the Java Virtual Machine (JVM), where option is one of the options described on the reference page for the Java launcher\&. For example, \f3-J-Xms48m\fR sets the startup memory to 48 MB\&. See java(1)\&. + +\fINote:\fR The \fICLASSPATH\fR, \f3-classpath\fR, \f3-bootclasspath\fR, and \f3-extdirs\fR options do not specify the classes used to run \f3javac\fR\&. Trying to customize the compiler implementation with these options and variables is risky and often does not accomplish what you want\&. If you must customize the complier implementation, then use the \f3-J\fR option to pass options through to the underlying \f3\fRJava launcher\&. +.TP +-nowarn +.br +Disables warning messages\&. This option operates the same as the \f3-Xlint:none\fR option\&. +.TP +-parameters +.br +Stores formal parameter names of constructors and methods in the generated class file so that the method \f3java\&.lang\&.reflect\&.Executable\&.getParameters\fR from the Reflection API can retrieve them\&. +.TP +-proc: [\fInone\fR, \fIonly\fR] +.br +Controls whether annotation processing and compilation are done\&. \f3-proc:none\fR means that compilation takes place without annotation processing\&. \f3-proc:only\fR means that only annotation processing is done, without any subsequent compilation\&. +.TP +-processor \fIclass1\fR [,\fIclass2\fR,\fIclass3\fR\&.\&.\&.] +.br Names of the annotation processors to run\&. This bypasses the default discovery process\&. -.RE -.PP -\-processorpath \fIpath\fR -.RS 4 +.TP +-processorpath \fIpath\fR +.br Specifies where to find annotation processors\&. If this option is not used, then the class path is searched for processors\&. -.RE -.PP -\-s \fIdir\fR -.RS 4 -Specifies the directory where to place the generated source files\&. The directory must already exist because -\fBjavac\fR -does not create it\&. If a class is part of a package, then the compiler puts the source file in a subdirectory that reflects the package name and creates directories as needed\&. -.sp -If you specify -\fB\-s /home/mysrc\fR -and the class is called -\fBcom\&.mypackage\&.MyClass\fR, then the source file is put in -\fB/home/mysrc/com/mypackage/MyClass\&.java\fR\&. -.RE -.PP -\-source \fIrelease\fR -.RS 4 -Specifies the version of source code accepted\&. The following values for -\fBrelease\fR -are allowed: -.PP +.TP +-s \fIdir\fR +.br +Specifies the directory where to place the generated source files\&. The directory must already exist because \f3javac\fR does not create it\&. If a class is part of a package, then the compiler puts the source file in a subdirectory that reflects the package name and creates directories as needed\&. + +If you specify \f3-s /home/mysrc\fR and the class is called \f3com\&.mypackage\&.MyClass\fR, then the source file is put in \f3/home/mysrc/com/mypackage/MyClass\&.java\fR\&. +.TP +-source \fIrelease\fR +.br +Specifies the version of source code accepted\&. The following values for \f3release\fR are allowed: +.RS +.TP 1\&.3 -.RS 4 The compiler does not support assertions, generics, or other language features introduced after Java SE 1\&.3\&. -.RE -.PP +.TP 1\&.4 -.RS 4 The compiler accepts code containing assertions, which were introduced in Java SE 1\&.4\&. -.RE -.PP +.TP 1\&.5 -.RS 4 The compiler accepts code containing generics and other language features introduced in Java SE 5\&. -.RE -.PP +.TP 5 -.RS 4 Synonym for 1\&.5\&. -.RE -.PP +.TP 1\&.6 -.RS 4 No language changes were introduced in Java SE 6\&. However, encoding errors in source files are now reported as errors instead of warnings as in earlier releases of Java Platform, Standard Edition\&. -.RE -.PP +.TP 6 -.RS 4 Synonym for 1\&.6\&. -.RE -.PP +.TP 1\&.7 -.RS 4 The compiler accepts code with features introduced in Java SE 7\&. -.RE -.PP +.TP 7 -.RS 4 Synonym for 1\&.7\&. -.RE -.PP +.TP 1\&.8 -.RS 4 This is the default value\&. The compiler accepts code with features introduced in Java SE 8\&. -.RE -.PP +.TP 8 -.RS 4 Synonym for 1\&.8\&. -.RE -.RE -.PP -\-sourcepath \fIsourcepath\fR -.RS 4 +.RE + +.TP +-sourcepath \fIsourcepath\fR +.br Specifies the source code path to search for class or interface definitions\&. As with the user class path, source path entries are separated by colons (:) on Oracle Solaris and semicolons on Windows and can be directories, JAR archives, or ZIP archives\&. If packages are used, then the local path name within the directory or archive must reflect the package name\&. -.sp -\fBNote:\fR -Classes found through the class path might be recompiled when their source files are also found\&. See Searching for Types\&. -.RE -.PP -\-verbose -.RS 4 + +\fINote:\fR Classes found through the class path might be recompiled when their source files are also found\&. See Searching for Types\&. +.TP +-verbose +.br Uses verbose output, which includes information about each class loaded and each source file compiled\&. -.RE -.PP -\-version -.RS 4 +.TP +-version +.br Prints release information\&. -.RE -.PP -\-werror -.RS 4 +.TP +-werror +.br Terminates compilation when warnings occur\&. -.RE -.PP -\-X -.RS 4 +.TP +-X +.br Displays information about nonstandard options and exits\&. -.RE -.SS "Cross\-Compilation Options" -.PP -By default, classes are compiled against the bootstrap and extension classes of the platform that -\fBjavac\fR -shipped with\&. But -\fBjavac\fR -also supports cross\-compiling, where classes are compiled against a bootstrap and extension classes of a different Java platform implementation\&. It is important to use the -\fB\-bootclasspath\fR -and -\fB\-extdirs\fR -options when cross\-compiling\&. -.PP -\-target \fIversion\fR -.RS 4 +.SS CROSS-COMPILATION\ OPTIONS +By default, classes are compiled against the bootstrap and extension classes of the platform that \f3javac\fR shipped with\&. But \f3javac\fR also supports cross-compiling, where classes are compiled against a bootstrap and extension classes of a different Java platform implementation\&. It is important to use the \f3-bootclasspath\fR and \f3-extdirs\fR options when cross-compiling\&. +.TP +-target \fIversion\fR +.br Generates class files that target a specified release of the virtual machine\&. Class files will run on the specified target and on later releases, but not on earlier releases of the JVM\&. Valid targets are 1\&.1, 1\&.2, 1\&.3, 1\&.4, 1\&.5 (also 5), 1\&.6 (also 6), 1\&.7 (also 7), and 1\&.8 (also 8)\&. -.sp -The default for the -\fB\-target\fR -option depends on the value of the -\fB\-source\fR -option: -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -If the -\fB\-source\fR -option is not specified, then the value of the -\fB\-target\fR -option is 1\&.8 -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -If the -\fB\-source\fR -option is 1\&.2, then the value of the -\fB\-target\fR -option is 1\&.4 -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -If the -\fB\-source\fR -option is 1\&.3, then the value of the -\fB\-target\fR -option is 1\&.4 -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -If the -\fB\-source\fR -option is 1\&.5, then the value of the -\fB\-target\fR -option is 1\&.8 -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -If the -\fB\-source\fR -option is 1\&.6, then the value of the -\fB\-target\fR -is option 1\&.8 -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -If the -\fB\-source\fR -option is 1\&.7, then the value of the -\fB\-target\fR -is option 1\&.8 -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} -For all other values of the -\fB\-source\fR -option, the value of the -\fB\-target\fR -option is the value of the -\fB\-source\fR -option\&. -.RE -.RE -.PP -\-bootclasspath \fIbootclasspath\fR -.RS 4 -Cross\-compiles against the specified set of boot classes\&. As with the user class path, boot class path entries are separated by colons (:) and can be directories, JAR archives, or ZIP archives\&. -.RE -.SS "Compact Profile Option" -.PP -Beginning with JDK 8, the -\fBjavac\fR -compiler supports compact profiles\&. With compact profiles, applications that do not require the entire Java platform can be deployed and run with a smaller footprint\&. The compact profiles feature could be used to shorten the download time for applications from app stores\&. This feature makes for more compact deployment of Java applications that bundle the JRE\&. This feature is also useful in small devices\&. -.PP -The supported profile values are -\fBcompact1\fR, -\fBcompact2\fR, and -\fBcompact3\fR\&. These are additive layers\&. Each higher\-numbered compact profile contains all of the APIs in profiles with smaller number names\&. + +The default for the \f3-target\fR option depends on the value of the \f3-source\fR option: +.RS +.TP 0.2i +\(bu +If the \f3-source\fR option is not specified, then the value of the \f3-target\fR option is 1\&.8 +.TP 0.2i +\(bu +If the \f3-source\fR option is 1\&.2, then the value of the \f3-target\fR option is 1\&.4 +.TP 0.2i +\(bu +If the \f3-source\fR option is 1\&.3, then the value of the \f3-target\fR option is 1\&.4 +.TP 0.2i +\(bu +If the \f3-source\fR option is 1\&.5, then the value of the \f3-target\fR option is 1\&.8 +.TP 0.2i +\(bu +If the \f3-source\fR option is 1\&.6, then the value of the \f3-target\fR is option 1\&.8 +.TP 0.2i +\(bu +If the \f3-source\fR option is 1\&.7, then the value of the \f3-target\fR is option 1\&.8 +.TP 0.2i +\(bu +For all other values of the \f3-source\fR option, the value of the \f3-target\fR option is the value of the \f3-source\fR option\&. +.RE + +.TP +-bootclasspath \fIbootclasspath\fR +.br +Cross-compiles against the specified set of boot classes\&. As with the user class path, boot class path entries are separated by colons (:) and can be directories, JAR archives, or ZIP archives\&. +.SS COMPACT\ PROFILE\ OPTION +Beginning with JDK 8, the \f3javac\fR compiler supports compact profiles\&. With compact profiles, applications that do not require the entire Java platform can be deployed and run with a smaller footprint\&. The compact profiles feature could be used to shorten the download time for applications from app stores\&. This feature makes for more compact deployment of Java applications that bundle the JRE\&. This feature is also useful in small devices\&. .PP -\-profile -.RS 4 +The supported profile values are \f3compact1\fR, \f3compact2\fR, and \f3compact3\fR\&. These are additive layers\&. Each higher-numbered compact profile contains all of the APIs in profiles with smaller number names\&. +.TP +-profile +.br When using compact profiles, this option specifies the profile name when compiling\&. For example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac \-profile compact1 Hello\&.java\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3javac \-profile compact1 Hello\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp + + javac does not compile source code that uses any Java SE APIs that is not in the specified profile\&. Here is an example of the error message that results from attempting to compile such source code: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBcd jdk1\&.8\&.0/bin\fR -\fB\&./javac \-profile compact1 Paint\&.java\fR -\fBPaint\&.java:5: error: Applet is not available in profile \*(Aqcompact1\*(Aq\fR -\fBimport java\&.applet\&.Applet;\fR - -.fi -.if n \{\ -.RE -.\} -In this example, you can correct the error by modifying the source to not use the -\fBApplet\fR -class\&. You could also correct the error by compiling without the \-profile option\&. Then the compilation would be run against the full set of Java SE APIs\&. (None of the compact profiles include the -\fBApplet\fR -class\&.) -.sp -An alternative way to compile with compact profiles is to use the -\fB\-bootclasspath\fR -option to specify a path to an -\fBrt\&.jar\fR -file that specifies a profile\*(Aqs image\&. Using the -\fB\-profile\fR -option instead does not require a profile image to be present on the system at compile time\&. This is useful when cross\-compiling\&. -.RE -.SS "Nonstandard Options" -.PP -\-Xbootclasspath/p:\fIpath\fR -.RS 4 +.sp +.nf +\f3cd jdk1\&.8\&.0/bin\fP +.fi +.nf +\f3\&./javac \-profile compact1 Paint\&.java\fP +.fi +.nf +\f3Paint\&.java:5: error: Applet is not available in profile \&'compact1\&'\fP +.fi +.nf +\f3import java\&.applet\&.Applet;\fP +.fi +.nf +\f3\fP +.fi +.sp + + +In this example, you can correct the error by modifying the source to not use the \f3Applet\fR class\&. You could also correct the error by compiling without the -profile option\&. Then the compilation would be run against the full set of Java SE APIs\&. (None of the compact profiles include the \f3Applet\fR class\&.) + +An alternative way to compile with compact profiles is to use the \f3-bootclasspath\fR option to specify a path to an \f3rt\&.jar\fR file that specifies a profile\&'s image\&. Using the \f3-profile\fR option instead does not require a profile image to be present on the system at compile time\&. This is useful when cross-compiling\&. +.SS NONSTANDARD\ OPTIONS +.TP +-Xbootclasspath/p:\fIpath\fR +.br Adds a suffix to the bootstrap class path\&. -.RE -.PP -\-Xbootclasspath/a:\fIpath\fR -.RS 4 +.TP +-Xbootclasspath/a:\fIpath\fR +.br Adds a prefix to the bootstrap class path\&. -.RE -.PP -\-Xbootclasspath/:\fIpath\fR -.RS 4 +.TP +-Xbootclasspath/:\fIpath\fR +.br Overrides the location of the bootstrap class files\&. -.RE -.PP -\-Xdoclint:[\-]\fIgroup\fR [\fI/access\fR] -.RS 4 -Enables or disables specific groups of checks, where -\fIgroup\fR -is one of the following values: -\fBaccessibility\fR, -\fBsyntax\fR, -\fBreference\fR, -\fBhtml\fR -or -\fBmissing\fR\&. For more information about these groups of checks see the -\fB\-Xdoclint\fR -option of the -\fBjavadoc\fR -command\&. The -\fB\-Xdoclint\fR -option is disabled by default in the -\fBjavac\fR -command\&. -.sp -The variable -\fIaccess\fR -specifies the minimum visibility level of classes and members that the -\fB\-Xdoclint\fR -option checks\&. It can have one of the following values (in order of most to least visible) : -\fBpublic\fR, -\fBprotected\fR, -\fBpackage\fR -and -\fBprivate\fR\&. For example, the following option checks classes and members (with all groups of checks) that have the access level protected and higher (which includes protected, package and public): -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-Xdoclint:all/protected\fR - -.fi -.if n \{\ -.RE -.\} +.TP +-Xdoclint:[-]\fIgroup\fR [\fI/access\fR] +.br +Enables or disables specific groups of checks, where \fIgroup\fR is one of the following values: \f3accessibility\fR, \f3syntax\fR, \f3reference\fR, \f3html\fR or \f3missing\fR\&. For more information about these groups of checks see the \f3-Xdoclint\fR option of the \f3javadoc\fR command\&. The \f3-Xdoclint\fR option is disabled by default in the \f3javac\fR command\&. + +The variable \fIaccess\fR specifies the minimum visibility level of classes and members that the \f3-Xdoclint\fR option checks\&. It can have one of the following values (in order of most to least visible) : \f3public\fR, \f3protected\fR, \f3package\fR and \f3private\fR\&. For example, the following option checks classes and members (with all groups of checks) that have the access level protected and higher (which includes protected, package and public): +.sp +.nf +\f3\-Xdoclint:all/protected\fP +.fi +.nf +\f3\fP +.fi +.sp + + The following option enables all groups of checks for all access levels, except it will not check for HTML errors for classes and members that have access level package and higher (which includes package and public): -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-Xdoclint:all,\-html/package\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\-Xdoclint:none -.RS 4 +.sp +.nf +\f3\-Xdoclint:all,\-html/package\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP +-Xdoclint:none +.br Disables all groups of checks\&. -.RE -.PP -\-Xdoclint:all[\fI/access\fR] -.RS 4 +.TP +-Xdoclint:all[\fI/access\fR] +.br Enables all groups of checks\&. -.RE -.PP -\-Xlint -.RS 4 -Enables all recommended warnings\&. In this release, enabling all available warnings is recommended\&. -.RE -.PP -\-Xlint:all -.RS 4 -Enables all recommended warnings\&. In this release, enabling all available warnings is recommended\&. -.RE -.PP -\-Xlint:none -.RS 4 +.TP +-Xlint +.br +\fI\fREnables all recommended warnings\&. In this release, enabling all available warnings is recommended\&. +.TP +-Xlint:all +.br +\fI\fREnables all recommended warnings\&. In this release, enabling all available warnings is recommended\&. +.TP +-Xlint:none +.br Disables all warnings\&. -.RE -.PP -\-Xlint:\fIname\fR -.RS 4 -Disables warning name\&. See Enable or Disable Warnings with the \-Xlint Option for a list of warnings you can disable with this option\&. -.RE -.PP -\-Xlint:\fI\-name\fR -.RS 4 -Disables warning name\&. See Enable or Disable Warnings with the \-Xlint Option with the -\fB\-Xlint\fR -option to get a list of warnings that you can disable with this option\&. -.RE -.PP -\-Xmaxerrs \fInumber\fR -.RS 4 +.TP +-Xlint:\fIname\fR +.br +Disables warning name\&. See Enable or Disable Warnings with the -Xlint Option for a list of warnings you can disable with this option\&. +.TP +-Xlint:\fI-name\fR +.br +Disables warning name\&. See Enable or Disable Warnings with the -Xlint Option with the \f3-Xlint\fR option to get a list of warnings that you can disable with this option\&. +.TP +-Xmaxerrs \fInumber\fR +.br Sets the maximum number of errors to print\&. -.RE -.PP -\-Xmaxwarns \fInumber\fR -.RS 4 +.TP +-Xmaxwarns \fInumber\fR +.br Sets the maximum number of warnings to print\&. -.RE -.PP -\-Xstdout \fIfilename\fR -.RS 4 -Sends compiler messages to the named file\&. By default, compiler messages go to -\fBSystem\&.err\fR\&. -.RE -.PP -\-Xprefer:[\fInewer,source\fR] -.RS 4 -Specifies which file to read when both a source file and class file are found for a type\&. (See Searching for Types)\&. If the -\fB\-Xprefer:newer\fR -option is used, then it reads the newer of the source or class file for a type (default)\&. If the -\fB\-Xprefer:source\fR -option is used, then it reads the source file\&. Use \-\fBXprefer:source\fR -when you want to be sure that any annotation processors can access annotations declared with a retention policy of -\fBSOURCE\fR\&. -.RE -.PP -\-Xpkginfo:[\fIalways\fR,\fIlegacy\fR,\fInonempty\fR] -.RS 4 -Control whether javac generates -\fBpackage\-info\&.class\fR -files from package\-info\&.java files\&. Possible mode arguments for this option include the following\&. -.PP +.TP +-Xstdout \fIfilename\fR +.br +Sends compiler messages to the named file\&. By default, compiler messages go to \f3System\&.err\fR\&. +.TP +-Xprefer:[\fInewer,source\fR] +.br +Specifies which file to read when both a source file and class file are found for a type\&. (See Searching for Types)\&. If the \f3-Xprefer:newer\fR option is used, then it reads the newer of the source or class file for a type (default)\&. If the \f3-Xprefer:source\fR option is used, then it reads the source file\&. Use -\f3Xprefer:source\fR when you want to be sure that any annotation processors can access annotations declared with a retention policy of \f3SOURCE\fR\&. +.TP +-Xpkginfo:[\fIalways\fR,\fIlegacy\fR,\fInonempty\fR] +.br +Control whether javac generates \f3package-info\&.class\fR files from package-info\&.java files\&. Possible mode arguments for this option include the following\&. +.RS +.TP always -.RS 4 -Always generate a -\fBpackage\-info\&.class\fR -file for every -\fBpackage\-info\&.java\fR -file\&. This option may be useful if you use a build system such as Ant, which checks that each -\fB\&.java\fR -file has a corresponding -\fB\&.class\fR -file\&. -.RE -.PP +Always generate a \f3package-info\&.class\fR file for every \f3package-info\&.java\fR file\&. This option may be useful if you use a build system such as Ant, which checks that each \f3\&.java\fR file has a corresponding \f3\&.class\fR file\&. +.TP legacy -.RS 4 -Generate a -\fBpackage\-info\&.class\fR -file only if package\-info\&.java contains annotations\&. Don\*(Aqt generate a -\fBpackage\-info\&.class\fR -file if package\-info\&.java only contains comments\&. -.sp -\fBNote:\fR -A -\fBpackage\-info\&.class\fR -file might be generated but be empty if all the annotations in the package\-info\&.java file have -\fBRetentionPolicy\&.SOURCE\fR\&. -.RE -.PP +Generate a \f3package-info\&.class\fR file only if package-info\&.java contains annotations\&. Don\&'t generate a \f3package-info\&.class\fR file if package-info\&.java only contains comments\&. + +\fINote:\fR A \f3package-info\&.class\fR file might be generated but be empty if all the annotations in the package-info\&.java file have \f3RetentionPolicy\&.SOURCE\fR\&. +.TP nonempty -.RS 4 -Generate a -\fBpackage\-info\&.class\fR -file only if package\-info\&.java contains annotations with -\fBRetentionPolicy\&.CLASS\fR -or -\fBRetentionPolicy\&.RUNTIME\fR\&. -.RE -.RE -.PP -\-Xprint -.RS 4 +Generate a \f3package-info\&.class\fR file only if package-info\&.java contains annotations with \f3RetentionPolicy\&.CLASS\fR or \f3RetentionPolicy\&.RUNTIME\fR\&. +.RE + +.TP +-Xprint +.br Prints a textual representation of specified types for debugging purposes\&. Perform neither annotation processing nor compilation\&. The format of the output could change\&. -.RE -.PP -\-XprintProcessorInfo -.RS 4 +.TP +-XprintProcessorInfo +.br Prints information about which annotations a processor is asked to process\&. -.RE -.PP -\-XprintRounds -.RS 4 +.TP +-XprintRounds +.br Prints information about initial and subsequent annotation processing rounds\&. -.RE -.SH "ENABLE OR DISABLE WARNINGS WITH THE -XLINT OPTION" -.PP -Enable warning -\fIname\fR -with the -\fB\-Xlint:name\fR -option, where -\fBname\fR -is one of the following warning names\&. Note that you can disable a warning with the -\fB\-Xlint:\-name:\fR -option\&. -.PP +.SH ENABLE\ OR\ DISABLE\ WARNINGS\ WITH\ THE\ -XLINT\ OPTION +Enable warning \fIname\fR with the \f3-Xlint:name\fR option, where \f3name\fR is one of the following warning names\&. Note that you can disable a warning with the \f3-Xlint:-name:\fR option\&. +.TP cast -.RS 4 Warns about unnecessary and redundant casts, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBString s = (String) "Hello!"\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP +.sp +.nf +\f3String s = (String) "Hello!"\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP classfile -.RS 4 Warns about issues related to class file contents\&. -.RE -.PP +.TP deprecation -.RS 4 Warns about the use of deprecated items, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjava\&.util\&.Date myDate = new java\&.util\&.Date();\fR -\fBint currentDay = myDate\&.getDay();\fR - -.fi -.if n \{\ -.RE -.\} -The method -\fBjava\&.util\&.Date\&.getDay\fR -has been deprecated since JDK 1\&.1 -.RE -.PP -dep\-ann -.RS 4 -Warns about items that are documented with an -\fB@deprecated\fR -Javadoc comment, but do not have a -\fB@Deprecated\fR -annotation, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB/**\fR -\fB * @deprecated As of Java SE 7, replaced by {@link #newMethod()}\fR -\fB */\fR -\fBpublic static void deprecatedMethood() { }\fR -\fBpublic static void newMethod() { }\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP +.sp +.nf +\f3java\&.util\&.Date myDate = new java\&.util\&.Date();\fP +.fi +.nf +\f3int currentDay = myDate\&.getDay();\fP +.fi +.nf +\f3\fP +.fi +.sp + + +The method \f3java\&.util\&.Date\&.getDay\fR has been deprecated since JDK 1\&.1 +.TP +dep-ann +Warns about items that are documented with an \f3@deprecated\fR Javadoc comment, but do not have a \f3@Deprecated\fR annotation, for example: +.sp +.nf +\f3/**\fP +.fi +.nf +\f3 * @deprecated As of Java SE 7, replaced by {@link #newMethod()}\fP +.fi +.nf +\f3 */\fP +.fi +.nf +\f3public static void deprecatedMethood() { }\fP +.fi +.nf +\f3public static void newMethod() { }\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP divzero -.RS 4 Warns about division by the constant integer 0, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBint divideByZero = 42 / 0;\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP +.sp +.nf +\f3int divideByZero = 42 / 0;\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP empty -.RS 4 -Warns about empty statements after -\fBif \fRstatements, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBclass E {\fR -\fB void m() {\fR -\fB if (true) ;\fR -\fB }\fR -\fB}\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP +Warns about empty statements after \f3if\fRstatements, for example: +.sp +.nf +\f3class E {\fP +.fi +.nf +\f3 void m() {\fP +.fi +.nf +\f3 if (true) ;\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3}\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP fallthrough -.RS 4 -Checks the switch blocks for fall\-through cases and provides a warning message for any that are found\&. Fall\-through cases are cases in a switch block, other than the last case in the block, whose code does not include a break statement, allowing code execution to fall through from that case to the next case\&. For example, the code following the case 1 label in this switch block does not end with a break statement: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBswitch (x) {\fR -\fBcase 1:\fR -\fB System\&.out\&.println("1");\fR -\fB // No break statement here\&.\fR -\fBcase 2:\fR -\fB System\&.out\&.println("2");\fR -\fB}\fR - -.fi -.if n \{\ -.RE -.\} -If the -\fB\-Xlint:fallthrough\fR -option was used when compiling this code, then the compiler emits a warning about possible fall\-through into case, with the line number of the case in question\&. -.RE -.PP +Checks the switch blocks for fall-through cases and provides a warning message for any that are found\&. Fall-through cases are cases in a switch block, other than the last case in the block, whose code does not include a break statement, allowing code execution to fall through from that case to the next case\&. For example, the code following the case 1 label in this switch block does not end with a break statement: +.sp +.nf +\f3switch (x) {\fP +.fi +.nf +\f3case 1:\fP +.fi +.nf +\f3 System\&.out\&.println("1");\fP +.fi +.nf +\f3 // No break statement here\&.\fP +.fi +.nf +\f3case 2:\fP +.fi +.nf +\f3 System\&.out\&.println("2");\fP +.fi +.nf +\f3}\fP +.fi +.nf +\f3\fP +.fi +.sp + + +If the \f3-Xlint:fallthrough\fR option was used when compiling this code, then the compiler emits a warning about possible fall-through into case, with the line number of the case in question\&. +.TP finally -.RS 4 -Warns about -\fBfinally\fR -clauses that cannot complete normally, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBpublic static int m() {\fR -\fB try {\fR -\fB throw new NullPointerException();\fR -\fB } catch (NullPointerException(); {\fR -\fB System\&.err\&.println("Caught NullPointerException\&.");\fR -\fB return 1;\fR -\fB } finally {\fR -\fB return 0;\fR -\fB }\fR -\fB }\fR - -.fi -.if n \{\ -.RE -.\} -The compiler generates a warning for the -\fBfinally\fR -block in this example\&. When the -\fBint\fR -method is called, it returns a value of 0\&. A -\fBfinally\fR -block executes when the -\fBtry\fR -block exits\&. In this example, when control is transferred to the -\fBcatch\fR -block, the -\fBint\fR -method exits\&. However, the -\fBfinally\fR -block must execute, so it is executed, even though control was transferred outside the method\&. -.RE -.PP +Warns about \f3finally\fR clauses that cannot complete normally, for example: +.sp +.nf +\f3public static int m() {\fP +.fi +.nf +\f3 try {\fP +.fi +.nf +\f3 throw new NullPointerException();\fP +.fi +.nf +\f3 } catch (NullPointerException(); {\fP +.fi +.nf +\f3 System\&.err\&.println("Caught NullPointerException\&.");\fP +.fi +.nf +\f3 return 1;\fP +.fi +.nf +\f3 } finally {\fP +.fi +.nf +\f3 return 0;\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3\fP +.fi +.sp + + +The compiler generates a warning for the \f3finally\fR block in this example\&. When the \f3int\fR method is called, it returns a value of 0\&. A \f3finally\fR block executes when the \f3try\fR block exits\&. In this example, when control is transferred to the \f3catch\fR block, the \f3int\fR method exits\&. However, the \f3finally\fR block must execute, so it is executed, even though control was transferred outside the method\&. +.TP options -.RS 4 -Warns about issues that related to the use of command\-line options\&. See Cross\-Compilation Options\&. -.RE -.PP +Warns about issues that related to the use of command-line options\&. See Cross-Compilation Options\&. +.TP overrides -.RS 4 Warns about issues regarding method overrides\&. For example, consider the following two classes: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBpublic class ClassWithVarargsMethod {\fR -\fB void varargsMethod(String\&.\&.\&. s) { }\fR -\fB}\fR - -\fBpublic class ClassWithOverridingMethod extends ClassWithVarargsMethod {\fR -\fB @Override\fR -\fB void varargsMethod(String[] s) { }\fR -\fB}\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3public class ClassWithVarargsMethod {\fP +.fi +.nf +\f3 void varargsMethod(String\&.\&.\&. s) { }\fP +.fi +.nf +\f3}\fP +.fi +.nf +\f3\fP +.fi +.nf +\f3public class ClassWithOverridingMethod extends ClassWithVarargsMethod {\fP +.fi +.nf +\f3 @Override\fP +.fi +.nf +\f3 void varargsMethod(String[] s) { }\fP +.fi +.nf +\f3}\fP +.fi +.nf +\f3\fP +.fi +.sp + + The compiler generates a warning similar to the following:\&. -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBwarning: [override] varargsMethod(String[]) in ClassWithOverridingMethod \fR -\fBoverrides varargsMethod(String\&.\&.\&.) in ClassWithVarargsMethod; overriding\fR -\fBmethod is missing \*(Aq\&.\&.\&.\*(Aq\fR - -.fi -.if n \{\ -.RE -.\} -When the compiler encounters a -\fBvarargs\fR -method, it translates the -\fBvarargs\fR -formal parameter into an array\&. In the method -\fBClassWithVarargsMethod\&.varargsMethod\fR, the compiler translates the -\fBvarargs\fR -formal parameter -\fBString\&.\&.\&. s\fR -to the formal parameter -\fBString[] s\fR, an array, which matches the formal parameter of the method -\fBClassWithOverridingMethod\&.varargsMethod\fR\&. Consequently, this example compiles\&. -.RE -.PP +.sp +.nf +\f3warning: [override] varargsMethod(String[]) in ClassWithOverridingMethod \fP +.fi +.nf +\f3overrides varargsMethod(String\&.\&.\&.) in ClassWithVarargsMethod; overriding\fP +.fi +.nf +\f3method is missing \&'\&.\&.\&.\&'\fP +.fi +.nf +\f3\fP +.fi +.sp + + +When the compiler encounters a \f3varargs\fR method, it translates the \f3varargs\fR formal parameter into an array\&. In the method \f3ClassWithVarargsMethod\&.varargsMethod\fR, the compiler translates the \f3varargs\fR formal parameter \f3String\&.\&.\&. s\fR to the formal parameter \f3String[] s\fR, an array, which matches the formal parameter of the method \f3ClassWithOverridingMethod\&.varargsMethod\fR\&. Consequently, this example compiles\&. +.TP path -.RS 4 -Warns about invalid path elements and nonexistent path directories on the command line (with regard to the class path, the source path, and other paths)\&. Such warnings cannot be suppressed with the -\fB@SuppressWarnings\fR -annotation, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac \-Xlint:path \-classpath /nonexistentpath Example\&.java\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP +Warns about invalid path elements and nonexistent path directories on the command line (with regard to the class path, the source path, and other paths)\&. Such warnings cannot be suppressed with the \f3@SuppressWarnings\fR annotation, for example: +.sp +.nf +\f3javac \-Xlint:path \-classpath /nonexistentpath Example\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP processing -.RS 4 Warn about issues regarding annotation processing\&. The compiler generates this warning when you have a class that has an annotation, and you use an annotation processor that cannot handle that type of exception\&. For example, the following is a simple annotation processor: -.sp -\fBSource file AnnocProc\&.java\fR: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBimport java\&.util\&.*;\fR -\fBimport javax\&.annotation\&.processing\&.*;\fR -\fBimport javax\&.lang\&.model\&.*;\fR -\fBimport\&.javaz\&.lang\&.model\&.element\&.*;\fR - -\fB@SupportedAnnotationTypes("NotAnno")\fR -\fBpublic class AnnoProc extends AbstractProcessor {\fR -\fB public boolean process(Set elems, RoundEnvironment renv){\fR -\fB return true;\fR -\fB }\fR - -\fB public SourceVersion getSupportedSourceVersion() {\fR -\fB return SourceVersion\&.latest();\fR -\fB }\fR -\fB}\fR - -.fi -.if n \{\ -.RE -.\} -\fBSource file AnnosWithoutProcessors\&.java\fR: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB@interface Anno { }\fR -\fB \fR -\fB@Anno\fR -\fBclass AnnosWithoutProcessors { }\fR - -.fi -.if n \{\ -.RE -.\} -The following commands compile the annotation processor -\fBAnnoProc\fR, then run this annotation processor against the source file -\fBAnnosWithoutProcessors\&.java\fR: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac AnnoProc\&.java\fR -\fBjavac \-cp \&. \-Xlint:processing \-processor AnnoProc \-proc:only AnnosWithoutProcessors\&.java\fR - -.fi -.if n \{\ -.RE -.\} -When the compiler runs the annotation processor against the source file -\fBAnnosWithoutProcessors\&.java\fR, it generates the following warning: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBwarning: [processing] No processor claimed any of these annotations: Anno\fR -\fB \fR -.fi -.if n \{\ -.RE -.\} -To resolve this issue, you can rename the annotation defined and used in the class -\fBAnnosWithoutProcessors\fR -from -\fBAnno\fR -to -\fBNotAnno\fR\&. -.RE -.PP + +\fISource file AnnocProc\&.java\fR: +.sp +.nf +\f3import java\&.util\&.*;\fP +.fi +.nf +\f3import javax\&.annotation\&.processing\&.*;\fP +.fi +.nf +\f3import javax\&.lang\&.model\&.*;\fP +.fi +.nf +\f3import\&.javaz\&.lang\&.model\&.element\&.*;\fP +.fi +.nf +\f3\fP +.fi +.nf +\f3@SupportedAnnotationTypes("NotAnno")\fP +.fi +.nf +\f3public class AnnoProc extends AbstractProcessor {\fP +.fi +.nf +\f3 public boolean process(Set elems, RoundEnvironment renv){\fP +.fi +.nf +\f3 return true;\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3\fP +.fi +.nf +\f3 public SourceVersion getSupportedSourceVersion() {\fP +.fi +.nf +\f3 return SourceVersion\&.latest();\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3}\fP +.fi +.nf +\f3\fP +.fi +.sp + + +\fISource file AnnosWithoutProcessors\&.java\fR: +.sp +.nf +\f3@interface Anno { }\fP +.fi +.nf +\f3\fP +.fi +.nf +\f3@Anno\fP +.fi +.nf +\f3class AnnosWithoutProcessors { }\fP +.fi +.nf +\f3\fP +.fi +.sp + + +The following commands compile the annotation processor \f3AnnoProc\fR, then run this annotation processor against the source file \f3AnnosWithoutProcessors\&.java\fR: +.sp +.nf +\f3javac AnnoProc\&.java\fP +.fi +.nf +\f3javac \-cp \&. \-Xlint:processing \-processor AnnoProc \-proc:only AnnosWithoutProcessors\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp + + +When the compiler runs the annotation processor against the source file \f3AnnosWithoutProcessors\&.java\fR, it generates the following warning: +.sp +.nf +\f3warning: [processing] No processor claimed any of these annotations: Anno\fP +.fi +.nf +\f3\fP +.fi +.sp + + +To resolve this issue, you can rename the annotation defined and used in the class \f3AnnosWithoutProcessors\fR from \f3Anno\fR to \f3NotAnno\fR\&. +.TP rawtypes -.RS 4 -Warns about unchecked operations on raw types\&. The following statement generates a -\fBrawtypes\fR -warning: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBvoid countElements(List l) { \&.\&.\&. }\fR - -.fi -.if n \{\ -.RE -.\} -The following example does not generate a -\fBrawtypes\fR -warning -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBvoid countElements(List l) { \&.\&.\&. }\fR - -.fi -.if n \{\ -.RE -.\} -\fBList\fR -is a raw type\&. However, -\fBList\fR -is an unbounded wildcard parameterized type\&. Because -\fBList\fR -is a parameterized interface, always specify its type argument\&. In this example, the -\fBList\fR -formal argument is specified with an unbounded wildcard (\fB?\fR) as its formal type parameter, which means that the -\fBcountElements\fR -method can accept any instantiation of the -\fBList\fR -interface\&. -.RE -.PP +Warns about unchecked operations on raw types\&. The following statement generates a \f3rawtypes\fR warning: +.sp +.nf +\f3void countElements(List l) { \&.\&.\&. }\fP +.fi +.nf +\f3\fP +.fi +.sp + + +The following example does not generate a \f3rawtypes\fR warning +.sp +.nf +\f3void countElements(List l) { \&.\&.\&. }\fP +.fi +.nf +\f3\fP +.fi +.sp + + +\f3List\fR is a raw type\&. However, \f3List\fR is an unbounded wildcard parameterized type\&. Because \f3List\fR is a parameterized interface, always specify its type argument\&. In this example, the \f3List\fR formal argument is specified with an unbounded wildcard (\f3?\fR) as its formal type parameter, which means that the \f3countElements\fR method can accept any instantiation of the \f3List\fR interface\&. +.TP Serial -.RS 4 -Warns about missing -\fBserialVersionUID\fR -definitions on serializable classes, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBpublic class PersistentTime implements Serializable\fR -\fB{\fR -\fB private Date time;\fR -\fB \fR -\fB public PersistentTime() {\fR -\fB time = Calendar\&.getInstance()\&.getTime();\fR -\fB }\fR -\fB \fR -\fB public Date getTime() {\fR -\fB return time;\fR -\fB }\fR -\fB}\fR - -.fi -.if n \{\ -.RE -.\} +Warns about missing \f3serialVersionUID\fR definitions on serializable classes, for example: +.sp +.nf +\f3public class PersistentTime implements Serializable\fP +.fi +.nf +\f3{\fP +.fi +.nf +\f3 private Date time;\fP +.fi +.nf +\f3\fP +.fi +.nf +\f3 public PersistentTime() {\fP +.fi +.nf +\f3 time = Calendar\&.getInstance()\&.getTime();\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3\fP +.fi +.nf +\f3 public Date getTime() {\fP +.fi +.nf +\f3 return time;\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3}\fP +.fi +.nf +\f3\fP +.fi +.sp + + The compiler generates the following warning: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBwarning: [serial] serializable class PersistentTime has no definition of\fR -\fBserialVersionUID\fR - -.fi -.if n \{\ -.RE -.\} -If a serializable class does not explicitly declare a field named -\fBserialVersionUID\fR, then the serialization runtime environment calculates a default -\fBserialVersionUID\fR -value for that class based on various aspects of the class, as described in the Java Object Serialization Specification\&. However, it is strongly recommended that all serializable classes explicitly declare -\fBserialVersionUID\fR -values because the default process of computing -\fBserialVersionUID\fR -vales is highly sensitive to class details that can vary depending on compiler implementations, and as a result, might cause an unexpected -\fBInvalidClassExceptions\fR -during deserialization\&. To guarantee a consistent -\fBserialVersionUID\fR -value across different Java compiler implementations, a serializable class must declare an explicit -\fBserialVersionUID\fR -value\&. -.RE -.PP +.sp +.nf +\f3warning: [serial] serializable class PersistentTime has no definition of\fP +.fi +.nf +\f3serialVersionUID\fP +.fi +.nf +\f3\fP +.fi +.sp + + +If a serializable class does not explicitly declare a field named \f3serialVersionUID\fR, then the serialization runtime environment calculates a default \f3serialVersionUID\fR value for that class based on various aspects of the class, as described in the Java Object Serialization Specification\&. However, it is strongly recommended that all serializable classes explicitly declare \f3serialVersionUID\fR values because the default process of computing \f3serialVersionUID\fR vales is highly sensitive to class details that can vary depending on compiler implementations, and as a result, might cause an unexpected \f3InvalidClassExceptions\fR during deserialization\&. To guarantee a consistent \f3serialVersionUID\fR value across different Java compiler implementations, a serializable class must declare an explicit \f3serialVersionUID\fR value\&. +.TP static -.RS 4 Warns about issues relating to the use of statics, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBclass XLintStatic {\fR -\fB static void m1() { }\fR -\fB void m2() { this\&.m1(); }\fR -\fB}\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3class XLintStatic {\fP +.fi +.nf +\f3 static void m1() { }\fP +.fi +.nf +\f3 void m2() { this\&.m1(); }\fP +.fi +.nf +\f3}\fP +.fi +.nf +\f3\fP +.fi +.sp + + The compiler generates the following warning: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBwarning: [static] static method should be qualified by type name, \fR -\fBXLintStatic, instead of by an expression\fR - -.fi -.if n \{\ -.RE -.\} -To resolve this issue, you can call the -\fBstatic\fR -method -\fBm1\fR -as follows: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBXLintStatic\&.m1();\fR - -.fi -.if n \{\ -.RE -.\} -Alternately, you can remove the -\fBstatic\fR -keyword from the declaration of the method -\fBm1\fR\&. -.RE -.PP +.sp +.nf +\f3warning: [static] static method should be qualified by type name, \fP +.fi +.nf +\f3XLintStatic, instead of by an expression\fP +.fi +.nf +\f3\fP +.fi +.sp + + +To resolve this issue, you can call the \f3static\fR method \f3m1\fR as follows: +.sp +.nf +\f3XLintStatic\&.m1();\fP +.fi +.nf +\f3\fP +.fi +.sp + + +Alternately, you can remove the \f3static\fR keyword from the declaration of the method \f3m1\fR\&. +.TP try -.RS 4 -Warns about issues relating to use of -\fBtry\fR -blocks, including try\-with\-resources statements\&. For example, a warning is generated for the following statement because the resource -\fBac\fR -declared in the -\fBtry\fR -block is not used: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBtry ( AutoCloseable ac = getResource() ) { // do nothing}\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP +Warns about issues relating to use of \f3try\fR blocks, including try-with-resources statements\&. For example, a warning is generated for the following statement because the resource \f3ac\fR declared in the \f3try\fR block is not used: +.sp +.nf +\f3try ( AutoCloseable ac = getResource() ) { // do nothing}\fP +.fi +.nf +\f3\fP +.fi +.sp + +.TP unchecked -.RS 4 Gives more detail for unchecked conversion warnings that are mandated by the Java Language Specification, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBList l = new ArrayList();\fR -\fBList ls = l; // unchecked warning\fR - -.fi -.if n \{\ -.RE -.\} -During type erasure, the types -\fBArrayList\fR -and -\fBList\fR -become -\fBArrayList\fR -and -\fBList\fR, respectively\&. -.sp -The -\fBls\fR -command has the parameterized type -\fBList\fR\&. When the -\fBList\fR -referenced by -\fBl\fR -is assigned to -\fBls\fR, the compiler generates an unchecked warning\&. At compile time, the compiler and JVM cannot determine whether -\fBl\fR -refers to a -\fBList\fR -type\&. In this case, -\fBl\fR -does not refer to a -\fBList\fR -type\&. As a result, heap pollution occurs\&. -.sp -A heap pollution situation occurs when the -\fBList\fR -object -\fBl\fR, whose static type is -\fBList\fR, is assigned to another -\fBList\fR -object, -\fBls\fR, that has a different static type, -\fBList\fR\&. However, the compiler still allows this assignment\&. It must allow this assignment to preserve backward compatibility with releases of Java SE that do not support generics\&. Because of type erasure, -\fBList\fR -and -\fBList\fR -both become -\fBList\fR\&. Consequently, the compiler allows the assignment of the object -\fBl\fR\fB,\fR -which has a raw type of -\fBList\fR, to the object -\fBls\fR\&. -.RE -.PP +.sp +.nf +\f3List l = new ArrayList();\fP +.fi +.nf +\f3List ls = l; // unchecked warning\fP +.fi +.nf +\f3\fP +.fi +.sp + + +During type erasure, the types \f3ArrayList\fR and \f3List\fR become \f3ArrayList\fR and \f3List\fR, respectively\&. + +The \f3ls\fR command has the parameterized type \f3List\fR\&. When the \f3List\fR referenced by \f3l\fR is assigned to \f3ls\fR, the compiler generates an unchecked warning\&. At compile time, the compiler and JVM cannot determine whether \f3l\fR refers to a \f3List\fR type\&. In this case, \f3l\fR does not refer to a \f3List\fR type\&. As a result, heap pollution occurs\&. + +A heap pollution situation occurs when the \f3List\fR object \f3l\fR, whose static type is \f3List\fR, is assigned to another \f3List\fR object, \f3ls\fR, that has a different static type, \f3List\fR\&. However, the compiler still allows this assignment\&. It must allow this assignment to preserve backward compatibility with releases of Java SE that do not support generics\&. Because of type erasure, \f3List\fR and \f3List\fR both become \f3List\fR\&. Consequently, the compiler allows the assignment of the object \f3l\fR\f3,\fR which has a raw type of \f3List\fR, to the object \f3ls\fR\&. +.TP varargs -.RS 4 -Warns about unsafe usages of variable arguments (\fBvarargs\fR) methods, in particular, those that contain non\-reifiable arguments, for example: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBpublic class ArrayBuilder {\fR -\fB public static void addToList (List listArg, T\&.\&.\&. elements) {\fR -\fB for (T x : elements) {\fR -\fB listArg\&.add(x);\fR -\fB }\fR -\fB }\fR -\fB}\fR - -.fi -.if n \{\ -.RE -.\} -\fBNote:\fR -A non\-reifiable type is a type whose type information is not fully available at runtime\&. -.sp -The compiler generates the following warning for the definition of the method -\fBArrayBuilder\&.addToList\fR -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBwarning: [varargs] Possible heap pollution from parameterized vararg type T\fR - -.fi -.if n \{\ -.RE -.\} -When the compiler encounters a varargs method, it translates the -\fBvarargs\fR -formal parameter into an array\&. However, the Java programming language does not permit the creation of arrays of parameterized types\&. In the method -\fBArrayBuilder\&.addToList\fR, the compiler translates the -\fBvarargs\fR -formal parameter -\fBT\&.\&.\&.\fR -elements to the formal parameter -\fBT[]\fR -elements, an array\&. However, because of type erasure, the compiler converts the -\fBvarargs\fR -formal parameter to -\fBObject[]\fR -elements\&. Consequently, there is a possibility of heap pollution\&. -.RE -.SH "COMMAND-LINE ARGUMENT FILES" -.PP -To shorten or simplify the -\fBjavac\fR -command, you can specify one or more files that contain arguments to the -\fBjavac\fR -command (except -\fB\-J\fR -options)\&. This enables you to create -\fBjavac\fR -commands of any length on any operating system\&. -.PP -An argument file can include -\fBjavac\fR -options and source file names in any combination\&. The arguments within a file can be separated by spaces or new line characters\&. If a file name contains embedded spaces, then put the whole file name in double quotation marks\&. +Warns about unsafe usages of variable arguments (\f3varargs\fR) methods, in particular, those that contain non-reifiable arguments, for example: +.sp +.nf +\f3public class ArrayBuilder {\fP +.fi +.nf +\f3 public static void addToList (List listArg, T\&.\&.\&. elements) {\fP +.fi +.nf +\f3 for (T x : elements) {\fP +.fi +.nf +\f3 listArg\&.add(x);\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3}\fP +.fi +.nf +\f3\fP +.fi +.sp + + +\fINote:\fR A non-reifiable type is a type whose type information is not fully available at runtime\&. + +The compiler generates the following warning for the definition of the method \f3ArrayBuilder\&.addToList\fR +.sp +.nf +\f3warning: [varargs] Possible heap pollution from parameterized vararg type T\fP +.fi +.nf +\f3\fP +.fi +.sp + + +When the compiler encounters a varargs method, it translates the \f3varargs\fR formal parameter into an array\&. However, the Java programming language does not permit the creation of arrays of parameterized types\&. In the method \f3ArrayBuilder\&.addToList\fR, the compiler translates the \f3varargs\fR formal parameter \f3T\&.\&.\&.\fR elements to the formal parameter \f3T[]\fR elements, an array\&. However, because of type erasure, the compiler converts the \f3varargs\fR formal parameter to \f3Object[]\fR elements\&. Consequently, there is a possibility of heap pollution\&. +.SH COMMAND-LINE\ ARGUMENT\ FILES +To shorten or simplify the \f3javac\fR command, you can specify one or more files that contain arguments to the \f3javac\fR command (except \f3-J\fR options)\&. This enables you to create \f3javac\fR commands of any length on any operating system\&. +.PP +An argument file can include \f3javac\fR options and source file names in any combination\&. The arguments within a file can be separated by spaces or new line characters\&. If a file name contains embedded spaces, then put the whole file name in double quotation marks\&. +.PP +File Names within an argument file are relative to the current directory, not the location of the argument file\&. Wild cards (*) are not allowed in these lists (such as for specifying \f3*\&.java\fR)\&. Use of the at sign (@) to recursively interpret files is not supported\&. The \f3-J\fR options are not supported because they are passed to the launcher, which does not support argument files\&. +.PP +When executing the \f3javac\fR command, pass in the path and name of each argument file with the at sign (@) leading character\&. When the \f3javac\fR command encounters an argument beginning with the at sign (@), it expands the contents of that file into the argument list\&. +.PP +\f3Example 1 Single Argument File\fR +.PP +You could use a single argument file named \f3argfile\fR to hold all \f3javac\fR arguments: +.sp +.nf +\f3javac @argfile\fP +.fi +.nf +\f3\fP +.fi +.sp +This argument file could contain the contents of both files shown in Example 2 .PP -File Names within an argument file are relative to the current directory, not the location of the argument file\&. Wild cards (*) are not allowed in these lists (such as for specifying -\fB*\&.java\fR)\&. Use of the at sign (@) to recursively interpret files is not supported\&. The -\fB\-J\fR -options are not supported because they are passed to the launcher, which does not support argument files\&. +\f3Example 2 Two Argument Files\fR .PP -When executing the -\fBjavac\fR -command, pass in the path and name of each argument file with the at sign (@) leading character\&. When the -\fBjavac\fR -command encounters an argument beginning with the at sign (@), it expands the contents of that file into the argument list\&. +You can create two argument files: one for the \f3javac\fR options and the other for the source file names\&. Note that the following lists have no line-continuation characters\&. .PP -\fBExample 1\fR -.br -Single Argument File -.RS 4 -You could use a single argument file named -\fBargfile\fR -to hold all -\fBjavac\fR -arguments: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac @argfile\fR - -.fi -.if n \{\ -.RE -.\} -This argument file could contain the contents of both files shown in Example 2 -.RE -.PP -\fBExample 2\fR -.br -Two Argument Files -.RS 4 -You can create two argument files: one for the -\fBjavac\fR -options and the other for the source file names\&. Note that the following lists have no line\-continuation characters\&. -.sp Create a file named options that contains the following: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-d classes\fR -.fi -.if n \{\ -.RE -.\} -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-g\fR -.fi -.if n \{\ -.RE -.\} -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB\-sourcepath /java/pubs/ws/1\&.3/src/share/classes\fR -.fi -.if n \{\ -.RE -.\} -.sp -.if n \{\ -.RS 4 -.\} -.nf - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3\-d classes\fP +.fi +.nf +\f3\-g\fP +.fi +.nf +\f3\-sourcepath /java/pubs/ws/1\&.3/src/share/classes\fP +.fi +.nf +\f3\fP +.fi +.sp Create a file named classes that contains the following: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBMyClass1\&.java\fR -\fBMyClass2\&.java\fR -\fBMyClass3\&.java\fR - -.fi -.if n \{\ -.RE -.\} -Then, run the -\fBjavac\fR -command as follows: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac @options @classes\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\fBExample 3\fR -.br -Argument Files with Paths -.RS 4 -The argument files can have paths, but any file names inside the files are relative to the current working directory (not -\fBpath1\fR -or -\fBpath2\fR): -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac @path1/options @path2/classes\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.SH "ANNOTATION PROCESSING" -.PP -The -\fBjavac\fR -command provides direct support for annotation processing, superseding the need for the separate annotation processing command, -\fBapt\fR\&. -.PP -The API for annotation processors is defined in the -\fBjavax\&.annotation\&.processing\fR -and j\fBavax\&.lang\&.model\fR -packages and subpackages\&. -.SS "How Annotation Processing Works" -.PP -Unless annotation processing is disabled with the -\fB\-proc:none\fR -option, the compiler searches for any annotation processors that are available\&. The search path can be specified with the -\fB\-processorpath\fR -option\&. If no path is specified, then the user class path is used\&. Processors are located by means of service provider\-configuration files named -\fBMETA\-INF/services/javax\&.annotation\&.processing\fR\&.Processor on the search path\&. Such files should contain the names of any annotation processors to be used, listed one per line\&. Alternatively, processors can be specified explicitly, using the -\fB\-processor\fR -option\&. +.sp +.nf +\f3MyClass1\&.java\fP +.fi +.nf +\f3MyClass2\&.java\fP +.fi +.nf +\f3MyClass3\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp +Then, run the \f3javac\fR command as follows: +.sp +.nf +\f3javac @options @classes\fP +.fi +.nf +\f3\fP +.fi +.sp +\f3Example 3 Argument Files with Paths\fR +.PP +The argument files can have paths, but any file names inside the files are relative to the current working directory (not \f3path1\fR or \f3path2\fR): +.sp +.nf +\f3javac @path1/options @path2/classes\fP +.fi +.nf +\f3\fP +.fi +.sp +.SH ANNOTATION\ PROCESSING +The \f3javac\fR command provides direct support for annotation processing, superseding the need for the separate annotation processing command, \f3apt\fR\&. +.PP +The API for annotation processors is defined in the \f3javax\&.annotation\&.processing\fR and j\f3avax\&.lang\&.model\fR packages and subpackages\&. +.SS HOW\ ANNOTATION\ PROCESSING\ WORKS +Unless annotation processing is disabled with the \f3-proc:none\fR option, the compiler searches for any annotation processors that are available\&. The search path can be specified with the \f3-processorpath\fR option\&. If no path is specified, then the user class path is used\&. Processors are located by means of service provider-configuration files named \f3META-INF/services/javax\&.annotation\&.processing\fR\&.Processor on the search path\&. Such files should contain the names of any annotation processors to be used, listed one per line\&. Alternatively, processors can be specified explicitly, using the \f3-processor\fR option\&. .PP After scanning the source files and classes on the command line to determine what annotations are present, the compiler queries the processors to determine what annotations they process\&. When a match is found, the processor is called\&. A processor can claim the annotations it processes, in which case no further attempt is made to find any processors for those annotations\&. After all of the annotations are claimed, the compiler does not search for additional processors\&. .PP If any processors generate new source files, then another round of annotation processing occurs: Any newly generated source files are scanned, and the annotations processed as before\&. Any processors called on previous rounds are also called on all subsequent rounds\&. This continues until no new source files are generated\&. .PP -After a round occurs where no new source files are generated, the annotation processors are called one last time, to give them a chance to complete any remaining work\&. Finally, unless the -\fB\-proc:only\fR -option is used, the compiler compiles the original and all generated source files\&. -.SS "Implicitly Loaded Source Files" -.PP -To compile a set of source files, the compiler might need to implicitly load additional source files\&. See Searching for Types\&. Such files are currently not subject to annotation processing\&. By default, the compiler gives a warning when annotation processing occurred and any implicitly loaded source files are compiled\&. The -\fB\-implicit\fR -option provides a way to suppress the warning\&. -.SH "SEARCHING FOR TYPES" -.PP +After a round occurs where no new source files are generated, the annotation processors are called one last time, to give them a chance to complete any remaining work\&. Finally, unless the \f3-proc:only\fR option is used, the compiler compiles the original and all generated source files\&. +.SS IMPLICITLY\ LOADED\ SOURCE\ FILES +To compile a set of source files, the compiler might need to implicitly load additional source files\&. See Searching for Types\&. Such files are currently not subject to annotation processing\&. By default, the compiler gives a warning when annotation processing occurred and any implicitly loaded source files are compiled\&. The \f3-implicit\fR option provides a way to suppress the warning\&. +.SH SEARCHING\ FOR\ TYPES To compile a source file, the compiler often needs information about a type, but the type definition is not in the source files specified on the command line\&. The compiler needs type information for every class or interface used, extended, or implemented in the source file\&. This includes classes and interfaces not explicitly mentioned in the source file, but that provide information through inheritance\&. .PP -For example, when you create a subclass -\fBjava\&.applet\&.Applet\fR, you are also using the ancestor classes of -\fBApplet\fR: -\fBjava\&.awt\&.Panel\fR, -\fBjava\&.awt\&.Container\fR, -\fBjava\&.awt\&.Component\fR, and -\fBjava\&.lang\&.Object\fR\&. -.PP -When the compiler needs type information, it searches for a source file or class file that defines the type\&. The compiler searches for class files first in the bootstrap and extension classes, then in the user class path (which by default is the current directory)\&. The user class path is defined by setting the -\fBCLASSPATH\fR -environment variable or by using the -\fB\-classpath\fR -option\&. -.PP -If you set the -\fB\-sourcepath\fR -option, then the compiler searches the indicated path for source files\&. Otherwise, the compiler searches the user class path for both class files and source files\&. -.PP -You can specify different bootstrap or extension classes with the -\fB\-bootclasspath\fR -and the -\fB\-extdirs\fR -options\&. See Cross\-Compilation Options\&. -.PP -A successful type search may produce a class file, a source file, or both\&. If both are found, then you can use the -\fB\-Xprefer\fR -option to instruct the compiler which to use\&. If -\fBnewer\fR -is specified, then the compiler uses the newer of the two files\&. If -\fBsource\fR -is specified, the compiler uses the source file\&. The default is -\fBnewer\fR\&. -.PP -If a type search finds a source file for a required type, either by itself, or as a result of the setting for the -\fB\-Xprefer\fR -option, then the compiler reads the source file to get the information it needs\&. By default the compiler also compiles the source file\&. You can use the -\fB\-implicit\fR -option to specify the behavior\&. If -\fBnone\fR -is specified, then no class files are generated for the source file\&. If -\fBclass\fR -is specified, then class files are generated for the source file\&. -.PP -The compiler might not discover the need for some type information until after annotation processing completes\&. When the type information is found in a source file and no -\fB\-implicit\fR -option is specified, the compiler gives a warning that the file is being compiled without being subject to annotation processing\&. To disable the warning, either specify the file on the command line (so that it will be subject to annotation processing) or use the -\fB\-implicit\fR -option to specify whether or not class files should be generated for such source files\&. -.SH "PROGRAMMATIC INTERFACE" -.PP -The -\fBjavac\fR -command supports the new Java Compiler API defined by the classes and interfaces in the -\fBjavax\&.tools\fR -package\&. -.SS "Example" -.PP -To compile as though providing command\-line arguments, use the following syntax: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBJavaCompiler javac = ToolProvider\&.getSystemJavaCompiler();\fR - -.fi -.if n \{\ -.RE -.\} -.PP -The example writes diagnostics to the standard output stream and returns the exit code that -\fBjavac\fR -would give when called from the command line\&. -.PP -You can use other methods in the -\fBjavax\&.tools\&.JavaCompiler\fR -interface to handle diagnostics, control where files are read from and written to, and more\&. -.SS "Old Interface" -.PP -\fBNote:\fR -This API is retained for backward compatibility only\&. All new code should use the newer Java Compiler API\&. -.PP -The -\fBcom\&.sun\&.tools\&.javac\&.Main\fR -class provides two static methods to call the compiler from a program: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBpublic static int compile(String[] args);\fR -\fBpublic static int compile(String[] args, PrintWriter out);\fR - -.fi -.if n \{\ -.RE -.\} -.PP -The -\fBargs\fR -parameter represents any of the command\-line arguments that would typically be passed to the compiler\&. -.PP -The -\fBout\fR -parameter indicates where the compiler diagnostic output is directed\&. -.PP -The -\fBreturn\fR -value is equivalent to the -\fBexit\fR -value from -\fBjavac\fR\&. -.PP -\fBNote:\fR -All other classes and methods found in a package with names that start with -\fBcom\&.sun\&.tools\&.javac\fR -(subpackages of -\fBcom\&.sun\&.tools\&.javac\fR) are strictly internal and subject to change at any time\&. -.SH "EXAMPLES" -.PP -\fBExample 1\fR -.br -Compile a Simple Program -.RS 4 -This example shows how to compile the -\fBHello\&.java\fR -source file in the greetings directory\&. The class defined in -\fBHello\&.java\fR -is called -\fBgreetings\&.Hello\fR\&. The greetings directory is the package directory both for the source file and the class file and is underneath the current directory\&. This makes it possible to use the default user class path\&. It also makes it unnecessary to specify a separate destination directory with the -\fB\-d\fR -option\&. -.sp -The source code in -\fBHello\&.java\fR: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBpackage greetings;\fR -\fB \fR -\fBpublic class Hello {\fR -\fB public static void main(String[] args) {\fR -\fB for (int i=0; i < args\&.length; i++) {\fR -\fB System\&.out\&.println("Hello " + args[i]);\fR -\fB }\fR -\fB }\fR -\fB}\fR - -.fi -.if n \{\ -.RE -.\} +For example, when you create a subclass \f3java\&.applet\&.Applet\fR, you are also using the ancestor classes of \f3Applet\fR: \f3java\&.awt\&.Panel\fR, \f3java\&.awt\&.Container\fR, \f3java\&.awt\&.Component\fR, and \f3java\&.lang\&.Object\fR\&. +.PP +When the compiler needs type information, it searches for a source file or class file that defines the type\&. The compiler searches for class files first in the bootstrap and extension classes, then in the user class path (which by default is the current directory)\&. The user class path is defined by setting the \f3CLASSPATH\fR environment variable or by using the \f3-classpath\fR option\&. +.PP +If you set the \f3-sourcepath\fR option, then the compiler searches the indicated path for source files\&. Otherwise, the compiler searches the user class path for both class files and source files\&. +.PP +You can specify different bootstrap or extension classes with the \f3-bootclasspath\fR and the \f3-extdirs\fR options\&. See Cross-Compilation Options\&. +.PP +A successful type search may produce a class file, a source file, or both\&. If both are found, then you can use the \f3-Xprefer\fR option to instruct the compiler which to use\&. If \f3newer\fR is specified, then the compiler uses the newer of the two files\&. If \f3source\fR is specified, the compiler uses the source file\&. The default is \f3newer\fR\&. +.PP +If a type search finds a source file for a required type, either by itself, or as a result of the setting for the \f3-Xprefer\fR option, then the compiler reads the source file to get the information it needs\&. By default the compiler also compiles the source file\&. You can use the \f3-implicit\fR option to specify the behavior\&. If \f3none\fR is specified, then no class files are generated for the source file\&. If \f3class\fR is specified, then class files are generated for the source file\&. +.PP +The compiler might not discover the need for some type information until after annotation processing completes\&. When the type information is found in a source file and no \f3-implicit\fR option is specified, the compiler gives a warning that the file is being compiled without being subject to annotation processing\&. To disable the warning, either specify the file on the command line (so that it will be subject to annotation processing) or use the \f3-implicit\fR option to specify whether or not class files should be generated for such source files\&. +.SH PROGRAMMATIC\ INTERFACE +The \f3javac\fR command supports the new Java Compiler API defined by the classes and interfaces in the \f3javax\&.tools\fR package\&. +.SS EXAMPLE +To compile as though providing command-line arguments, use the following syntax: +.sp +.nf +\f3JavaCompiler javac = ToolProvider\&.getSystemJavaCompiler();\fP +.fi +.nf +\f3\fP +.fi +.sp +The example writes diagnostics to the standard output stream and returns the exit code that \f3javac\fR would give when called from the command line\&. +.PP +You can use other methods in the \f3javax\&.tools\&.JavaCompiler\fR interface to handle diagnostics, control where files are read from and written to, and more\&. +.SS OLD\ INTERFACE +\fINote:\fR This API is retained for backward compatibility only\&. All new code should use the newer Java Compiler API\&. +.PP +The \f3com\&.sun\&.tools\&.javac\&.Main\fR class provides two static methods to call the compiler from a program: +.sp +.nf +\f3public static int compile(String[] args);\fP +.fi +.nf +\f3public static int compile(String[] args, PrintWriter out);\fP +.fi +.nf +\f3\fP +.fi +.sp +The \f3args\fR parameter represents any of the command-line arguments that would typically be passed to the compiler\&. +.PP +The \f3out\fR parameter indicates where the compiler diagnostic output is directed\&. +.PP +The \f3return\fR value is equivalent to the \f3exit\fR value from \f3javac\fR\&. +.PP +\fINote:\fR All other classes and methods found in a package with names that start with \f3com\&.sun\&.tools\&.javac\fR (subpackages of \f3com\&.sun\&.tools\&.javac\fR) are strictly internal and subject to change at any time\&. +.SH EXAMPLES +\f3Example 1 Compile a Simple Program\fR +.PP +This example shows how to compile the \f3Hello\&.java\fR source file in the greetings directory\&. The class defined in \f3Hello\&.java\fR is called \f3greetings\&.Hello\fR\&. The greetings directory is the package directory both for the source file and the class file and is underneath the current directory\&. This makes it possible to use the default user class path\&. It also makes it unnecessary to specify a separate destination directory with the \f3-d\fR option\&. +.PP +The source code in \f3Hello\&.java\fR: +.sp +.nf +\f3package greetings;\fP +.fi +.nf +\f3\fP +.fi +.nf +\f3public class Hello {\fP +.fi +.nf +\f3 public static void main(String[] args) {\fP +.fi +.nf +\f3 for (int i=0; i < args\&.length; i++) {\fP +.fi +.nf +\f3 System\&.out\&.println("Hello " + args[i]);\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3 }\fP +.fi +.nf +\f3}\fP +.fi +.nf +\f3\fP +.fi +.sp Compile greetings\&.Hello: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac greetings/Hello\&.java\fR - -.fi -.if n \{\ -.RE -.\} -Run -\fBgreetings\&.Hello\fR: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjava greetings\&.Hello World Universe Everyone\fR -\fBHello World\fR -\fBHello Universe\fR -\fBHello Everyone\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\fBExample 2\fR -.br -Compile Multiple Source Files -.RS 4 -This example compiles the -\fBAloha\&.java\fR, -\fBGutenTag\&.java\fR, -\fBHello\&.java\fR, and -\fBHi\&.java\fR -source files in the -\fBgreetings\fR -package\&. -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fB% javac greetings/*\&.java\fR -\fB% ls greetings\fR -\fBAloha\&.class GutenTag\&.class Hello\&.class Hi\&.class\fR -\fBAloha\&.java GutenTag\&.java Hello\&.java Hi\&.java\fR - -.fi -.if n \{\ -.RE -.\} -.RE +.sp +.nf +\f3javac greetings/Hello\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp +Run \f3greetings\&.Hello\fR: +.sp +.nf +\f3java greetings\&.Hello World Universe Everyone\fP +.fi +.nf +\f3Hello World\fP +.fi +.nf +\f3Hello Universe\fP +.fi +.nf +\f3Hello Everyone\fP +.fi +.nf +\f3\fP +.fi +.sp +\f3Example 2 Compile Multiple Source Files\fR +.PP +This example compiles the \f3Aloha\&.java\fR, \f3GutenTag\&.java\fR, \f3Hello\&.java\fR, and \f3Hi\&.java\fR source files in the \f3greetings\fR package\&. +.sp +.nf +\f3% javac greetings/*\&.java\fP +.fi +.nf +\f3% ls greetings\fP +.fi +.nf +\f3Aloha\&.class GutenTag\&.class Hello\&.class Hi\&.class\fP +.fi +.nf +\f3Aloha\&.java GutenTag\&.java Hello\&.java Hi\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp +\f3Example 3 Specify a User Class Path\fR .PP -\fBExample 3\fR -.br -Specify a User Class Path -.RS 4 After changing one of the source files in the previous example, recompile it: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBpwd\fR -\fB/examples\fR -\fBjavac greetings/Hi\&.java\fR - -.fi -.if n \{\ -.RE -.\} -Because -\fBgreetings\&.Hi\fR -refers to other classes in the -\fBgreetings\fR -package, the compiler needs to find these other classes\&. The previous example works because the default user class path is the directory that contains the package directory\&. If you want to recompile this file without concern for which directory you are in, then add the examples directory to the user class path by setting -\fBCLASSPATH\fR\&. This example uses the -\fB\-classpath\fR -option\&. -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac \-classpath /examples /examples/greetings/Hi\&.java\fR - -.fi -.if n \{\ -.RE -.\} -If you change -\fBgreetings\&.Hi\fR -to use a banner utility, then that utility also needs to be accessible through the user class path\&. -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac \-classpath /examples:/lib/Banners\&.jar \e\fR -\fB /examples/greetings/Hi\&.java\fR - -.fi -.if n \{\ -.RE -.\} -To execute a class in the -\fBgreetings\fR -package, the program needs access to the -\fBgreetings\fR -package, and to the classes that the -\fBgreetings\fR -classes use\&. -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjava \-classpath /examples:/lib/Banners\&.jar greetings\&.Hi\fR - -.fi -.if n \{\ -.RE -.\} -.RE -.PP -\fBExample 4\fR -.br -Separate Source Files and Class Files -.RS 4 -The following example uses -\fBjavac\fR -to compile code that runs on JVM 1\&.7\&. -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac \-source 1\&.7 \-target 1\&.7 \-bootclasspath jdk1\&.7\&.0/lib/rt\&.jar \e \fR -\fB\-extdirs "" OldCode\&.java\fR - -.fi -.if n \{\ -.RE -.\} -The -\fB\-source 1\&.7\fR -option specifies that release 1\&.7 (or 7) of the Java programming language be used to compile -\fBOldCode\&.java\fR\&. The option -\fB\-target 1\&.7\fR -option ensures that the generated class files are compatible with JVM 1\&.7\&. Note that in most cases, the value of the -\fB\-target\fR -option is the value of the -\fB\-source\fR -option; in this example, you can omit the -\fB\-target\fR -option\&. -.sp -You must specify the -\fB\-bootclasspath\fR -option to specify the correct version of the bootstrap classes (the -\fBrt\&.jar\fR -library)\&. If not, then the compiler generates a warning: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac \-source 1\&.7 OldCode\&.java\fR -\fBwarning: [options] bootstrap class path not set in conjunction with \fR -\fB\-source 1\&.7\fR - -.fi -.if n \{\ -.RE -.\} +.sp +.nf +\f3pwd\fP +.fi +.nf +\f3/examples\fP +.fi +.nf +\f3javac greetings/Hi\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp +Because \f3greetings\&.Hi\fR refers to other classes in the \f3greetings\fR package, the compiler needs to find these other classes\&. The previous example works because the default user class path is the directory that contains the package directory\&. If you want to recompile this file without concern for which directory you are in, then add the examples directory to the user class path by setting \f3CLASSPATH\fR\&. This example uses the \f3-classpath\fR option\&. +.sp +.nf +\f3javac \-classpath /examples /examples/greetings/Hi\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp +If you change \f3greetings\&.Hi\fR to use a banner utility, then that utility also needs to be accessible through the user class path\&. +.sp +.nf +\f3javac \-classpath /examples:/lib/Banners\&.jar \e\fP +.fi +.nf +\f3 /examples/greetings/Hi\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp +To execute a class in the \f3greetings\fR package, the program needs access to the \f3greetings\fR package, and to the classes that the \f3greetings\fR classes use\&. +.sp +.nf +\f3java \-classpath /examples:/lib/Banners\&.jar greetings\&.Hi\fP +.fi +.nf +\f3\fP +.fi +.sp +\f3Example 4 Separate Source Files and Class Files\fR +.PP +The following example uses \f3javac\fR to compile code that runs on JVM 1\&.7\&. +.sp +.nf +\f3javac \-source 1\&.7 \-target 1\&.7 \-bootclasspath jdk1\&.7\&.0/lib/rt\&.jar \e \fP +.fi +.nf +\f3\-extdirs "" OldCode\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp +The \f3-source 1\&.7\fR option specifies that release 1\&.7 (or 7) of the Java programming language be used to compile \f3OldCode\&.java\fR\&. The option \f3-target 1\&.7\fR option ensures that the generated class files are compatible with JVM 1\&.7\&. Note that in most cases, the value of the \f3-target\fR option is the value of the \f3-source\fR option; in this example, you can omit the \f3-target\fR option\&. +.PP +You must specify the \f3-bootclasspath\fR option to specify the correct version of the bootstrap classes (the \f3rt\&.jar\fR library)\&. If not, then the compiler generates a warning: +.sp +.nf +\f3javac \-source 1\&.7 OldCode\&.java\fP +.fi +.nf +\f3warning: [options] bootstrap class path not set in conjunction with \fP +.fi +.nf +\f3\-source 1\&.7\fP +.fi +.nf +\f3\fP +.fi +.sp If you do not specify the correct version of bootstrap classes, then the compiler uses the old language rules (in this example, it uses version 1\&.7 of the Java programming language) combined with the new bootstrap classes, which can result in class files that do not work on the older platform (in this case, Java SE 7) because reference to nonexistent methods can get included\&. -.RE .PP -\fBExample 5\fR -.br -Cross Compile -.RS 4 -This example uses -\fBjavac\fR -to compile code that runs on JVM 1\&.7\&. -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac \-source 1\&.7 \-target 1\&.7 \-bootclasspath jdk1\&.7\&.0/lib/rt\&.jar \e\fR -\fB \-extdirs "" OldCode\&.java\fR - -.fi -.if n \{\ -.RE -.\} -The\fB \-source 1\&.7\fR -option specifies that release 1\&.7 (or 7) of the Java programming language to be used to compile OldCode\&.java\&. The -\fB\-target 1\&.7\fR -option ensures that the generated class files are compatible with JVM 1\&.7\&. In most cases, the value of the -\fB\-target\fR -is the value of -\fB\-source\fR\&. In this example, the -\fB\-target\fR -option is omitted\&. -.sp -You must specify the -\fB\-bootclasspath\fR -option to specify the correct version of the bootstrap classes (the -\fBrt\&.jar\fR -library)\&. If not, then the compiler generates a warning: -.sp -.if n \{\ -.RS 4 -.\} -.nf -\fBjavac \-source 1\&.7 OldCode\&.java\fR -\fBwarning: [options] bootstrap class path not set in conjunction with \-source 1\&.7\fR - -.fi -.if n \{\ -.RE -.\} +\f3Example 5 Cross Compile\fR +.PP +This example uses \f3javac\fR to compile code that runs on JVM 1\&.7\&. +.sp +.nf +\f3javac \-source 1\&.7 \-target 1\&.7 \-bootclasspath jdk1\&.7\&.0/lib/rt\&.jar \e\fP +.fi +.nf +\f3 \-extdirs "" OldCode\&.java\fP +.fi +.nf +\f3\fP +.fi +.sp +The\f3-source 1\&.7\fR option specifies that release 1\&.7 (or 7) of the Java programming language to be used to compile OldCode\&.java\&. The \f3-target 1\&.7\fR option ensures that the generated class files are compatible with JVM 1\&.7\&. +.PP +You must specify the \f3-bootclasspath\fR option to specify the correct version of the bootstrap classes (the \f3rt\&.jar\fR library)\&. If not, then the compiler generates a warning: +.sp +.nf +\f3javac \-source 1\&.7 OldCode\&.java\fP +.fi +.nf +\f3warning: [options] bootstrap class path not set in conjunction with \-source 1\&.7\fP +.fi +.nf +\f3\fP +.fi +.sp If you do not specify the correct version of bootstrap classes, then the compiler uses the old language rules combined with the new bootstrap classes\&. This combination can result in class files that do not work on the older platform (in this case, Java SE 7) because reference to nonexistent methods can get included\&. In this example, the compiler uses release 1\&.7 of the Java programming language\&. -.RE -.SH "SEE ALSO" -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.SH SEE\ ALSO +.TP 0.2i +\(bu java(1) -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu jdb(1) -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu javah(1) -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu javadoc(1) -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu jar(1) -.RE -.sp -.RS 4 -.ie n \{\ -\h'-04'\(bu\h'+03'\c -.\} -.el \{\ -.sp -1 -.IP \(bu 2.3 -.\} +.TP 0.2i +\(bu jdb(1) -.RE -.br -'pl 8.5i -'bp +.RE +.br +'pl 8.5i +'bp diff --git a/src/bsd/doc/man/javadoc.1 b/src/bsd/doc/man/javadoc.1 index b48535a38..f4b342b55 100644 --- a/src/bsd/doc/man/javadoc.1 +++ b/src/bsd/doc/man/javadoc.1 @@ -1,5 +1,5 @@ '\" t -.\" Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved. +.\" Copyright (c) 1994, 2015, Oracle and/or its affiliates. All rights reserved. .\" .\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. .\" @@ -23,12 +23,12 @@ .\" .\" Arch: generic .\" Software: JDK 8 -.\" Date: 10 May 2011 +.\" Date: 03 March 2015 .\" SectDesc: Basic Tools .\" Title: javadoc.1 .\" .if n .pl 99999 -.TH javadoc 1 "10 May 2011" "JDK 8" "Basic Tools" +.TH javadoc 1 "03 March 2015" "JDK 8" "Basic Tools" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- @@ -209,7 +209,7 @@ The \f3package-info\&.java\fR file can contain a package comment of the followin \f3package java\&.lang\&.applet;\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -251,7 +251,7 @@ File: \f3java/applet/package\&.html\fR \f3initialize, start, and stop the applet\&. \fP .fi .nf -\f3\fR +\f3\fP .fi .nf \f3@since 1\&.0 \fP @@ -266,7 +266,7 @@ File: \f3java/applet/package\&.html\fR \f3\fP .fi .nf -\f3\fR +\f3\fP .fi .sp The \f3package\&.html\fR file is a typical HTML file and does not include a package declaration\&. The content of the package comment file is written in HTML with one exception\&. The documentation comment should not include the comment separators \f3/**\fR and \f3*/\fR or leading asterisks\&. When writing the comment, make the first sentence a summary about the package, and do not put a title or any other text between the \f3\fR tag and the first sentence\&. You can include package tags\&. All block tags must appear after the main description\&. If you add an \f3@see\fR tag in a package comment file, then it must have a fully qualified name\&. @@ -334,7 +334,7 @@ All links to the unprocessed files must be included in the code because the \f3j \f3 */\fP .fi .nf -\f3\fR +\f3\fP .fi .sp .SS TEST\ AND\ TEMPLATE\ FILES @@ -350,7 +350,7 @@ If you want your test files to belong to either an unnamed package or to a packa \f3com/package1/test\-files/\fP .fi .nf -\f3\fR +\f3\fP .fi .sp If your test files contain documentation comments, then you can set up a separate run of the \f3javadoc\fR command to produce test file documentation by passing in their test source file names with wild cards, such as \f3com/package1/test-files/*\&.java\fR\&. @@ -560,7 +560,7 @@ The \f3javadoc\fR command generates a declaration at the start of each class, in \f3implements Serializable\fP .fi .nf -\f3\fR +\f3\fP .fi .sp The declaration for the \f3Boolean\&.valueOf\fR method is: @@ -569,7 +569,7 @@ The declaration for the \f3Boolean\&.valueOf\fR method is: \f3public static Boolean valueOf(String s)\fP .fi .nf -\f3\fR +\f3\fP .fi .sp The \f3javadoc\fR command can include the modifiers \f3public\fR, \f3protected\fR, \f3private\fR, \f3abstract\fR, \f3final\fR, \f3static\fR, \f3transient\fR, and \f3volatile\fR, but not \f3synchronized\fR or \f3native\fR\&. The \f3synchronized\fR and \f3native\fR modifiers are considered implementation detail and not part of the API specification\&. @@ -593,7 +593,7 @@ You can include documentation comments in the source code, ahead of declarations \f3 */\fP .fi .nf -\f3\fR +\f3\fP .fi .sp To save space you can put a comment on one line: @@ -602,7 +602,7 @@ To save space you can put a comment on one line: \f3/** This comment takes up only one line\&. */\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -623,19 +623,19 @@ A common mistake is to put an \f3import\fR statement between the class comment a \f3 */\fP .fi .nf -\f3\fR +\f3\fP .fi .nf \f3import com\&.example; // MISTAKE \- Important not to put import statement here\fP .fi .nf -\f3\fR +\f3\fP .fi .nf \f3public class Whatever{ }\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -657,7 +657,7 @@ A documentation comment has a main description followed by a tag section\&. The \f3 */\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -676,7 +676,7 @@ A tag is a special keyword within a documentation comment that the \f3javadoc\fR \f3 */\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -700,7 +700,7 @@ For example, entities for the less than symbol (<) and the greater than symbol ( \f3 */\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -730,7 +730,7 @@ The Java platform lets you declare multiple fields in a single statement, but th \f3public int x, y; // Avoid this \fP .fi .nf -\f3\fR +\f3\fP .fi .sp The \f3javadoc\fR command generates the following documentation from the previous code: @@ -739,7 +739,7 @@ The \f3javadoc\fR command generates the following documentation from the previou \f3public int x\fP .fi .nf -\f3\fR +\f3\fP .fi .sp The horizontal and vertical distances of point (x, y)\&. @@ -748,7 +748,7 @@ The horizontal and vertical distances of point (x, y)\&. \f3public int y\fP .fi .nf -\f3\fR +\f3\fP .fi .sp The horizontal and vertical distances of point (x, y)\&. @@ -872,7 +872,7 @@ In a documentation comment: \f3 */\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -899,11 +899,10 @@ In the main description block of a method\&. In this case, the main description .TP 0.2i \(bu In the text arguments of the \f3@return\fR, \f3@param,\fR and \f3@throws\fR tags of a method\&. In this case, the tag text is copied from the corresponding tag up the hierarchy\&. -.RE -.RS -See Method Comment Inheritance for a description of how comments are found in the inheritance hierarchy\&. Note that if this tag is missing, then the comment is or is not automatically inherited according to rules described in that section\&. +.RE + -.RE +See Method Comment Inheritance for a description of how comments are found in the inheritance hierarchy\&. Note that if this tag is missing, then the comment is or is not automatically inherited according to rules described in that section\&. .TP {@link \fIpackage\&.class#member label\fR} Introduced in JDK 1\&.2 @@ -920,7 +919,7 @@ For example, here is a comment that refers to the \f3getComponentAt(int, int)\fR \f3Use the {@link #getComponentAt(int, int) getComponentAt} method\&.\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -931,7 +930,7 @@ From this code, the standard doclet generates the following HTML (assuming it re \f3Use the getComponentAt method\&.\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -942,7 +941,7 @@ The previous line appears on the web page as: \f3Use the getComponentAt method\&.\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -982,7 +981,7 @@ Example of a type parameter of a class: \f3}\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -1014,7 +1013,7 @@ Example of a type parameter of a method: \f3}\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -1071,7 +1070,7 @@ A space is the delimiter between \f3package\&.class#member\fR and \f3label\fR\&. \f3 */\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -1091,7 +1090,7 @@ The standard doclet produces HTML that is similar to: \f3\fP .fi .nf -\f3\fR +\f3\fP .fi .sp @@ -1128,7 +1127,7 @@ Specify a Name \f3@see #constructor(Type argname, Type argname,\&.\&.\&.) \fP .fi .nf -\f3\fR +\f3\fP .fi .nf \f3\fIReferencing another class in the current or imported packages\fR\fP @@ -1155,7 +1154,7 @@ Specify a Name \f3@see Class \fP .fi .nf -\f3\fR +\f3\fP .fi .nf \f3\fIReferencing an element in another package (fully qualified)\fR\fP @@ -1185,7 +1184,7 @@ Specify a Name \f3@see package\fP .fi .nf -\f3\fR +\f3\fP .fi .sp \f3\fRNotes about the previous listing: @@ -1215,7 +1214,7 @@ The current class or interface\&. Any enclosing classes and interfaces searching the closest first\&. .TP 0.4i 3\&. -Any superclasses and superonterfaces, searching the closest first\&. +Any superclasses and superinterfaces, searching the closest first\&. .TP 0.4i 4\&. The current package\&. @@ -1307,7 +1306,7 @@ The comment to the right shows how the name appears when the \f3@see\fR tag is i \f3@see "The Java Programming Language" // "The Java Programming Language" \fP .fi .nf -\f3\fR +\f3\fP .fi .sp \fINote:\fR You can extend the \f3@se\fR\f3e\fR tag to link to classes not being documented with the \f3-link\fR option\&. @@ -1317,7 +1316,7 @@ Introduced in JDK 1\&.2 Used in the documentation comment for a default serializable field\&. See Documenting Serializable Fields and Data for a Class at http://docs\&.oracle\&.com/javase/8/docs/platform/serialization/spec/serial-arch\&.html#5251 -See also Oracle\(cqs Criteria for Including Classes in the Serialilzed Form Specification at http://www\&.oracle\&.com/technetwork/java/javase/documentation/serialized-criteria-137781\&.html +See also Oracle\(cqs Criteria for Including Classes in the Serialized Form Specification at http://www\&.oracle\&.com/technetwork/java/javase/documentation/serialized-criteria-137781\&.html An optional \f3field-description\fR should explain the meaning of the field and list the acceptable values\&. When needed, the description can span multiple lines\&. The standard doclet adds this information to the serialized form page\&. See Cross-Reference Pages\&. @@ -1331,13 +1330,12 @@ A public or protected class that implements \f3Serializable\fR is included unles .TP 0.2i \(bu A private or package-private class that implements \f3Serializable\fR is excluded unless that class (or its package) is marked with the \f3@serial include\fR tag\&. -.RE -.RS +.RE + + For example, the \f3javax\&.swing\fR package is marked with the \f3@serial\fR\f3exclude\fR tag in package\&.html or package-info\&.java\&. The public class \f3java\&.security\&.BasicPermission\fR is marked with the \f3@serial exclude\fR tag\&. The package-private class \f3java\&.util\&.PropertyPermissionCollection\fR is marked with the \f3@serial include\fR tag\&. The \f3@serial\fR tag at the class level overrides the \f3@serial\fR tag at the package level\&. - -.RE .TP @serialData \fIdata-description\fR Introduced in JDK 1\&.2 @@ -1387,7 +1385,7 @@ Displays constant values\&. When the \f3{@value}\fR tag is used without an argum \f3public static final String SCRIPT_START = "