Working on OpenJDK using NetBeans This note describes how to work on the OpenJDK from NetBeans. We've provided several NetBeans projects as starting points. Below we'll describe how to use them, as well as how to create your own. Getting Started In addition to the source bundle for Open JDK, you'll need to download and install copies of the JDK and of NetBeans 6. And if you want to run tests on the JDK (you do want to run tests, right?), you'll need to install the jtreg test harness. In this note, when pathnames are not fully specified, they should be interpreted as being relative to the directory containing this README and the NetBeans projects themselves. The JDK build process is largely make-based, and is not exceptionally tolerant of pathnames with spaces in them (such as "Program Files". Please be sure to install everything in a directories whose paths don't have any spaces! Downloading the JDK You've probably done this a million times. Download and install it from http://java.sun.com/javase Downloading the OpenJDK sources Since you're reading this, d you've already downloaded the OpenJDK source bundle. Later in this document we'll refer to the location where you installed the Open JDK sources as *install-dir*. Downloading a pre-built, JDK 7 This will be necessary to do builds of some of the projects. In general, you want to download and install a pre-built JDK that corresponds to the OpenJDK sources you download. Building the entire OpenJDK depends on a few parts of the pre-built JDK. Get this from http://download.java.net/jdk7/binaries Note: For working on certain projects, like JMX and JConsole, you may find convenient to use a pre-built version of JDK 7 (or OpenJDK) rather than building your own. This will allow you to build only that part of the OpenJDK sources which correspond to that project. NetBeans 6 Yep, NetBeans *6*. Nope, not FCS'd yet. We're on the edge here, enjoy it! Get the latest working development build of NetBeans 6 from http://netbeans.org jtreg "jtreg" is the test harness for running OpenJDK's regression tests. Get it from http://openjdk.java.net/jtreg Ant NetBeans comes with ant, but if you use a separately-installed copy please make sure that it is at least version 1.7.0. Configuring Building OpenJDK is hard and complex. No, strike that. While it's not exactly "easy", we've got it down to *relatively* small set of properties you need to set. The NetBeans projects provided here share a fair amount of common structure. They share properties values where it makes sense. Each project loads properties from these properties files, in this order ${basedir}/nbproject/private/build.properties $HOME/.openjdk/${ant.project.name}-build.properties $HOME/.openjdk/build.properties ${basedir}/build.properties (${basedir} refers to the directory containing a particular NetBeans project.) The first time a property defined determines value: it is *not* overridden if it is read from properties files read later. The net result is that by carefully choosing where to define a property, you can have it for a specific project, all uses of a specific project (useful if you work on multiple copies of the OpenJDK sources), all projects, or only projects in a specific sandbox. With that in mind, please set the following properties. Presuming you want the same values for all your work, set them in $HOME/.openjdk/build.properties. * bootstrap.jdk Set to the location where you installed JDK 7. * jtreg.home Set to the location where you installed jtreg. * make.options Some of the projects invoke "make", since they compile native code. The make.options property is for passing information about what you installed where to make. Change the paths to fit your particular situation: make.options=\ ALT_BOOTDIR=/home/me/bin/jdk1.6.0 \ ALT_JDK_IMPORT_PATH=/home/me/bin/jdk1.7.0 \ OPENJDK=true The trailing '\' are important, so that make gets the above as a single set of options. You might want to add additional additional options: see the README for the project you're using for more information. And see *install-dir*/jdk/make/README-builds.html to read much more about building the JDK. Windows-specific configuration First, please note that the entire JDK cannot currently be built on Windows platforms. This will likely limit your ability to build make-based projects. See *install-dir*/jdk/make/README-builds.html for full information on issues with building on the Windows platform. That said, there are two ways to work with the Windows-required settings for the Microsoft tools. Either: * Set environment variables values in Windows Doing so means accessing the System control panel in Windows, and setting the environment variables there. By doing so, you can launch NetBeans by double-clicking its icon, and the environment variable values will be available. * Set environment variable values in a shell Doing so means adding the settings to an init file (e.g. .bashrc, .cshrc, etc.) or a file that you source before running NetBeans. In this case, you'll have to launch NetBeans from the command line in a shell in which you've set the environment variables. In either case, the end result should be that the settings are available to the make-based build process when it runs from within NetBeans. The make-based builds presumes that you're using cygwin, and expects to find "make" in c:\cygwin\bin\make. If you've installed cygwin elsewhere, set "make" in a properties file. Configuring Project Properties A note of caution is in order: These are NetBeans *freeform* projects. If you use the NetBeans GUI to examine them, things are likely to not look "right". Please don't edit them there, please instead use a text editor. Locale Requirements To build the Open JDK sources, be certain that you are using the "C" locale on Unix (R) platforms, or "English (United States)" locale on Windows. Platforms and architectures, oh my! The Open JDK can be built for a variety of operating system platforms and hardware architectures. The resulting builds are always placed in a directory which contains the platform and architecture as part of the pathname, as in *platform*-*arch*. For example, if you build the jdk project on a Linux platform running on x86 hardware, the resulting build will be in: *install-dir*/jdk/build/linux-i586 We've provided support for some platforms and architectures in common/architectures. Add another, if your needs require it. Provided NetBeans projects This section describes the NetBeans projects that help you work on particular parts of the JDK. While they're largely similar in structure and should work the way you expect NetBeans projects to work: edit, build, test, etc. But there are some differences. They don't all support the same targets (e.g., there's nothing to run in jarzip project). Some projects are built by invoking make, since they involve compilation of native code or other activities that cannot be done by javac. We call these "make-based", and call all others "ant-based". They all are configured by way of a build.properties file, which specifies what subdirectories of the JDK sources they manipulate, what directories contain their tests, whether they use make or ant, etc. The very first time you open any one of these projects on set of Open JDK sources, NetBeans will scan the entire set of sources, not just those for the project you opened. This will take a few minutes, but will ensure that Go To Type, Go To Source, and so on work as expected. Later, when you open other projects on the same Open JDK sources, there will be at most a slight delay. There's a README accompanying each project. Most are text files, which you can Open in NetBeans, some are HTML files, in which case unless you enjoy reading raw HTML, you're better off choosing the *View* menu item from the context menu, which will display the README in your web browser. Finally, note that these projects were all created by different people, and are while some attempt has been made to make them look and behave the same, they are maintained separately and will vary somewhat. The projects currently provided are: jdk (directory "jdk") A convenient starting point for the other projects, and from which you can build the entire OpenJDK. Please note that depending on your hardware, this could take a *very* long time. The results of the build are in *install-dir*/jdk/build/*platform*-*arch*. world (directory "world") This project builds both the Hotspot VM and all of JavaSE. Please note that pretty much regardless of your hardware, this *will* take a long time, and use *lots* of disk space (more than 3GB). The results of the build are in *install-dir*/build/*platform*-*arch* and *install-dir*/build/*platform*-*arch*-fastdebug. Consult the project's README file for details. AWT & Java2d (directory "awt2d") For working on AWT and Java2d. Supports running the Font2DTest demo. This is a make-based project: In order to build this project, you should build the jdk project first, since AWT and Java2d include native code. JConsole (directory "jconsole") For working on JConsole. Creates ../dist/lib/jconsole.jar. Supports running and debugging JConsole. This ant-based project does *not* require that you build the jdk project first, provided that you use a pre-built version of JDK 7. Java (TM) Management Extensions (JMX(TM)) API (directory "jmx") For working on JMX source code. Creates ../dist/lib/jmx.jar. This ant-based project does *not* require that you build the jdk project first, provided that you use a pre-built version of JDK 7. Jar & Zip (directory "jarzip") For working on jar & zip. It builds the zip library (including native code), the jar library, and the jar tool. Creates an executable jar program in ../build/*platform*-*arch*/bin/jar. This is a make-based project: In order to build this project, you should build the jdk project first, since AWT and Java2d include native code. Swing (directory "swing") For working on Swing. Creates ../dist/lib/swing.jar. Supports running and debugging the SampleTree demo. This ant-based project does *not* require that you build the jdk project first, provided that you use a pre-built version of JDK 7. In addition, there are projects for building the compiler, javadoc, and related tools, in the OpenJDK langtools component. These projects are separate from those described here, and have their own set of guidelines and conventions. For more details, see the README files in make/netbeans in the OpenJDK langtools component. Running Tests We use the jtreg test harness, described more fully at http://openjdk.java.net/jtreg The OpenJDK tests are in the default Java package, are public classes, and have a "static void main(String[] args)" with which they are invoked. Some tests are actually shell scripts, which might compile code, etc. jtreg is quite flexible. To run tests for a project, use *Test Project* from NetBeans. From the command line, you can invoke "ant jtreg" on any individual project's build.xml file. In either NetBeans of on the command line, jtreg prints summary output about the pass/fail nature of each test. An HTML report of the entire test run is ../build/*platform*-*arch*/jtreg/*ant-project-name*/JTreport/report.html In that same JTreport directory are also individual HTML files summarizing the test environment, test passes and failures, etc. More detail on any individual test is under ../build/*platform*-*arch*/jtreg/*ant-project-name*/JTwork. For example, details about the awt/Modal/SupportedTest/SupportedTest test are under the JTwork directory at the same pathname as the test itself in a ".jtr" file. For example: ../build/*platform*-*arch*/jtreg/*ant-project-name*/JTwork/awt/Modal/SupportedTest/SupportedTest.jtr Sometimes you will see that running jtreg has resulted in a failure. This does not always mean that a test has an error in it. Jtreg distinguishes between these two cases. There are a number of tests that are "ignored", and not run, and these are reported as failures. You can run a single test by right clicking on it and choosing *Run File* from the context menu. Similarly, you can debug a single test by choosing *Debug File*. Debugging Debugging is enabled by default in ant-based projects, as if "-g:lines,vars,source" were given. You can alter these settings via entries in one of the configuration properties files. For example: javac.debug=false javac.debuglevel= To debug a project or test, use NetBeans in the normal way, with *Debug Project* or *Debug File*. Note that not all projects provide a target that can be debugged, but tests can be debugged. Creating Javadoc You can create Javadoc for any of the projects: just choose *Generate Javadoc for Project* from the NetBeans menu. Your default browser will open up, displaying the just-generated javadoc. Javadoc gets generated into a separate subdirectory for each project. For example, the Jar & Zip project's javadoc gets generated in ../build/*platform*-*arch*/jtreg/*ant-project-name*/javadoc/jarzip Cleaning projects Each project can of course be cleaned. Make-based and ant-based projects differ a little in what exactly gets cleaned. In both cases, all jtreg results and javadoc are removed. In ant-based projects, project-specific files as determined by the project's build.properties file are removed from the classes and gensrc directories that are under ../build/*platform*-*arch*. In make-based projects, "make clean" is run in the same directories as "make all" is run when building the project. Please note that the jdk project is "special" with respect to cleaning: in this case, the entire ../build directory is removed. Similar for the world project. Creating your own NetBeans project The project's we've provided are hopefully a useful starting point, but chances are that you want to work on something else. This section will describe how to select an existing project, and then adapt it to your needs. Considerations The first consideration is whether or not the code in which you're interested needs anything beyond javac and copying of resources to build. If so, then you'll need to create a make-based project. If not, an ant-based project is possible. See the project descriptions above to learn which are make-based, and which are ant-based. The second consideration is to consider the files that you'll need. Each project is defined by 3 files: * build.xml This is the ant build script. For a make-based project, they tend to have a target for "make clean" and another for "make all", each of which invokes "make-run" in the same set of directories. Take a look at jarzip/build.xml for an example. For an ant-based project, there might be nothing, with all the work done via the declaration of properties in the build.properties file. Take a look at jconsole/build.xml for an example, and notice how it overrides the -pre-compile and -post-compile targets that are defined in common/shared.xml (where they are defined to do nothing). * build.properties This file defines the directories (and possibly files) that are included in and excluded from. Basically, a file is considered to be in a project if it is mentioned in the includes list, or is contained under a directory mentioned in that list, *unless* it is explicitly excluded or is contained under a directory that is excluded. Take a look awt2d/build.properties for an example. * nbproject/project.xml This file defines a project for NetBeans for a "freeform" project. Each declares several entity references, which are used later in the project. For an example, see javadoc/nbproject/project.xml, which is an ant-based project. Compare that with jarzip/nbproject/project.xml, which is make-based. Not much difference! That's because while the jarzip project is make-based, it does not have any platform-specifc native code. Contrast that with awt2d/nbproject/project.xml, which does have native code; notice that it uses platform-specific entity references. In summary, we recommend exploring the given projects, and choosing one that most closely suits our needs. Example: A project for working on collections Let's create a project to work with on the collections classes. There's no native code here, so an ant-based project will do. Therefore, the jconsole project is a reasonable project to use as a starting point. Clone the existing project Make a directory for the collections project next to the existing projects: % mkdir -p collections/nbproject Copy files from the jconsole project: % cp jconsole/build.properties collections % cp jconsole/build.xml collections % cp jconsole/nbproject/project.xml collections/nbproject Change the set of files included in the project The collections sources are all under one directory, and we want to include them all. The same is true of the tests. So edit collections/build.properties so that it contains these lines: includes=\ java/util/ excludes=\ java/util/Calendar.java,\ java/util/jar/,\ java/util/logging/,\ java/util/prefs/,\ java/util/regex/,\ java/util/spi/,\ java/util/zip/,\ **/*-XLocales.java.template jtreg.tests=\ java/util/**/*Collection/ \ java/util/**/*Map/ \ java/util/**/*Set/ \ java/util/**/*List/ Notice the trailing "/" in some of those pathnames: that tells NetBeans to treat the path as a directory and include (or exclude) everything beneath it in the hierarchy. Note also how we include java/util, but then exclude several directories under that which are not related to collections. The build.xml for collections is about as simple as can be. First, change the name of the project: Then remove the -pre-compile target from the build.xml. Change the -post-compile target to create collections.jar without any manifest, and to only contain the collections-related classes. The jar task now looks like this: Also, change the clean target to remove collections.jar instead of jconsole.jar. Now edit project.xml file. NetBeans uses an internal name and a user-visible name, both of which should be changed: Collections collections Inside of , you'll see actions defined for "run" and "debug". The Open JDK sources don't include any interesting Collections demos, but leave these here for now: Chances are you'll find or create some collections app of your own, and want to run and or debug it. Now, open the Collections project in NetBeans. You'll find that it operates just like all the other projects. If/when you want to have this project run a collections demo, change the run target in collections/build.xml to invoke it in whatever manner is appropriate for the app. From NetBeans, you should be able to run and debug the app, including setting breakpoints in collections code. Appendix 1: Customizations There are several ways to customize NetBeans projects. These projects share a common structure, based on common/shared.xml and common/make.xml. Because of that sharing, some mechanisms described below apply to most any project. Several properties can be user-defined (and several should not be user-defined!). There are different properties files read. Some default targets can be overridden. Property files When projects are started, and when when ant runs (whether from NetBeans or the command line), these properties files are loaded in the order shown: ${basedir}/nbproject/private/build.properties $HOME/.openjdk/${ant.project.name}-build.properties $HOME/.openjdk/build.properties ${basedir}/build.properties Recall that with ant, once a property is defined, its value cannot be changed, so it's "first one wins". To set or change a property for all your projects, put the change into $HOME/.openjdk/build.properties. This will affect all projects, regardless of how many copies of the Open JDK sources you have installed. Let's say you have 2 copies of the Open JDK sources installed on your machine. To set or change a property for only the jconsole projects, but for both of them, make the change in $HOME/.openjdk/${ant.project.name}-build.properties. If you wanted to make the change for only one of them, do it in that project's ${basedir}/build.properties or ${basedir}/nbproject/private/build.properties. Note that the ${basedir}/build.properties file is provided as part of the Open JDK sources. If you want to make a change for a particular project, you can do so there. To be sure that you don't ever accidentally check it in to the Open JDK sources, you might prefer to change it in ${basedir}/nbproject/private/build.properties. User-definable Properties You can provide your own definitions for the properties listed below. We don't recommend overriding the definitions of other properties. The following two properties should be set before you try to use the projects with NetBeans or ant: * bootstrap.jdk Default: None. Please set this, normally in $HOME/.openjdk/build.properties. * jtreg.home Default: None. Please set this, normally in $HOME/.openjdk/build.properties. These options are for configuring the behavior of make: * use.make Default: Not set. Set this, normally in ${basedir}/build.properties, for a project which is make-based. * make Default: The right make for the platform, at the normal location, set in *install-dir*/jdk/make/netbeans/common/make.xml * make.options Default: Empty string. Set this to any options you want to pass to make, normally in ${basedir}/build.properties. The remaining options are for use at your discretion: * javac.options Default: -Xlint * javac.debug Default: true * javac.debuglevel Default: lines,vars,source * javadoc.options Default: Empty string. Some projects will need to set this to increase the heap for running javadoc. For example, see the jconsole project. * javadoc.packagenames Default: "none". Set this only if your project has packages that should be javadoc'd which are outside of those listed in the javadoc target's packageset. See the jconsole project for an example. * jtreg.tests Default: None. Set this to a list of tests and/or directories containing regression tests, normally in ${basedir}/build.properties. * jtreg.options Default: Empty string. See http://openjdk.java.net/jtreg * jtreg.vm.options Default: Empty string. See http://openjdk.java.net/jtreg * jtreg.samevm Default: false. See http://openjdk.java.net/jtreg User-overridable Targets The following targets are provided for your convenience in customizing various standard actions of the build process. The default action for each one is to do nothing. These come in pairs, allowing your scripts to take some action before or after a standard action. * -pre-init Runs before any other initialization has been done. * -post-init Runs before after all other initialization has been done. * -pre-compile Runs before compilation, whether via ant or make. Note that in the case of make, it is before the -build-make target has run, not after each individual make-run has run. * -post-compile Runs after compilation, whether via ant or make. * -pre-jtreg Runs before regression tests are run. * -post-jtreg Runs before after regression tests are run. In a make-based project, you should override these targets to do the build and clean actions required of your project. * -build-make * -clean-make Known Issues Tests won't run: waiting for lock Occasionally when running tests, there will be a delay, followed by a message like this: Waiting to lock test result cache for /tmp/jdk/build/linux-i586/jtreg/jconsole/JTwork for 20 seconds The workaround is to stop the tests, rm -rf the offending jtreg/ directory by hand, and re-run the tests. Can't run nor debug a single test in the JConsole test In most projects, you can run a single test by opening it in the editor, and choosing Run File from the context menu. If you try this with the a JConsole test, instead you'll see that *all* tests from *all* projects are run. The workaround is to not try to run a single JConsole test. Debugging is similarly problematic (both running and debugging use the same underlying infrastructure). If you do Run File a JConsole tests, you can always stop them by pressing the stop button in the NetBeans output window. But you'll be surprised to learn that they are actually still running in the background. The only way out of this situation is to exit NetBeans. A few more tests will run, but after restarting NetBeans things will be OK. Attribution UNIX is a registered trademark in the United States and other countries, exclusively licensed through X/Open Company, Ltd.