diff --git a/src/share/classes/java/lang/AutoCloseable.java b/src/share/classes/java/lang/AutoCloseable.java index 0f7ed8e0dd618d5212a42ad5ffce1e592a6011c7..18c28fe887bd099b229cb3b1eb736b356be64ef8 100644 --- a/src/share/classes/java/lang/AutoCloseable.java +++ b/src/share/classes/java/lang/AutoCloseable.java @@ -41,6 +41,13 @@ public interface AutoCloseable { * be declared to throw more specific exceptions (or no exception * at all, if the close cannot fail). * + *

Note that unlike the {@link java.io.Closeable#close close} + * method of {@link java.io.Closeable}, this {@code close} method + * is not required to be idempotent. In other words, + * calling this {@code close} method more than once may have some + * visible side effect, unlike {@code Closeable.close} which is + * required to have no effect if called more than once. + * * @throws Exception if this resource cannot be closed */ void close() throws Exception; diff --git a/src/share/classes/java/lang/Throwable.java b/src/share/classes/java/lang/Throwable.java index 58478f90af4a238782eb6de5e2bd9fbb0eab418c..213f5f86d5cc8c1df842585e7af076b016986d56 100644 --- a/src/share/classes/java/lang/Throwable.java +++ b/src/share/classes/java/lang/Throwable.java @@ -28,12 +28,12 @@ import java.io.*; import java.util.*; /** - * The Throwable class is the superclass of all errors and + * The {@code Throwable} class is the superclass of all errors and * exceptions in the Java language. Only objects that are instances of this * class (or one of its subclasses) are thrown by the Java Virtual Machine or - * can be thrown by the Java throw statement. Similarly, only + * can be thrown by the Java {@code throw} statement. Similarly, only * this class or one of its subclasses can be the argument type in a - * catch clause. + * {@code catch} clause. * * For the purposes of compile-time checking of exceptions, {@code * Throwable} and any subclass of {@code Throwable} that is not also a @@ -73,11 +73,11 @@ import java.util.*; * permit the method to throw the cause directly. For example, suppose * a persistent collection conforms to the {@link java.util.Collection * Collection} interface, and that its persistence is implemented atop - * java.io. Suppose the internals of the add method + * {@code java.io}. Suppose the internals of the {@code add} method * can throw an {@link java.io.IOException IOException}. The implementation - * can communicate the details of the IOException to its caller - * while conforming to the Collection interface by wrapping the - * IOException in an appropriate unchecked exception. (The + * can communicate the details of the {@code IOException} to its caller + * while conforming to the {@code Collection} interface by wrapping the + * {@code IOException} in an appropriate unchecked exception. (The * specification for the persistent collection should indicate that it is * capable of throwing such exceptions.) * @@ -86,7 +86,7 @@ import java.util.*; * {@link #initCause(Throwable)} method. New throwable classes that * wish to allow causes to be associated with them should provide constructors * that take a cause and delegate (perhaps indirectly) to one of the - * Throwable constructors that takes a cause. For example: + * {@code Throwable} constructors that takes a cause. For example: *

  *     try {
  *         lowLevelOp();
@@ -94,10 +94,10 @@ import  java.util.*;
  *         throw new HighLevelException(le);  // Chaining-aware constructor
  *     }
  * 
- * Because the initCause method is public, it allows a cause to be + * Because the {@code initCause} method is public, it allows a cause to be * associated with any throwable, even a "legacy throwable" whose * implementation predates the addition of the exception chaining mechanism to - * Throwable. For example: + * {@code Throwable}. For example: *
  *     try {
  *         lowLevelOp();
@@ -121,28 +121,28 @@ import  java.util.*;
  * use the standard exception chaining mechanism, while continuing to
  * implement their "legacy" chaining mechanisms for compatibility.
  *
- * 

Further, as of release 1.4, many general purpose Throwable + *

Further, as of release 1.4, many general purpose {@code Throwable} * classes (for example {@link Exception}, {@link RuntimeException}, * {@link Error}) have been retrofitted with constructors that take * a cause. This was not strictly necessary, due to the existence of the - * initCause method, but it is more convenient and expressive to + * {@code initCause} method, but it is more convenient and expressive to * delegate to a constructor that takes a cause. * - *

By convention, class Throwable and its subclasses have two + *

By convention, class {@code Throwable} and its subclasses have two * constructors, one that takes no arguments and one that takes a - * String argument that can be used to produce a detail message. + * {@code String} argument that can be used to produce a detail message. * Further, those subclasses that might likely have a cause associated with * them should have two more constructors, one that takes a - * Throwable (the cause), and one that takes a - * String (the detail message) and a Throwable (the + * {@code Throwable} (the cause), and one that takes a + * {@code String} (the detail message) and a {@code Throwable} (the * cause). * *

Also introduced in release 1.4 is the {@link #getStackTrace()} method, * which allows programmatic access to the stack trace information that was * previously available only in text form, via the various forms of the * {@link #printStackTrace()} method. This information has been added to the - * serialized representation of this class so getStackTrace - * and printStackTrace will operate properly on a throwable that + * serialized representation of this class so {@code getStackTrace} + * and {@code printStackTrace} will operate properly on a throwable that * was obtained by deserialization. * * @author unascribed @@ -162,7 +162,7 @@ public class Throwable implements Serializable { /** * Specific details about the Throwable. For example, for - * FileNotFoundException, this contains the name of + * {@code FileNotFoundException}, this contains the name of * the file that could not be found. * * @serial @@ -212,7 +212,7 @@ public class Throwable implements Serializable { private static final String SUPPRESSED_CAPTION = "Suppressed: "; /** - * Constructs a new throwable with null as its detail message. + * Constructs a new throwable with {@code null} as its detail message. * The cause is not initialized, and may subsequently be initialized by a * call to {@link #initCause}. * @@ -242,7 +242,7 @@ public class Throwable implements Serializable { /** * Constructs a new throwable with the specified detail message and * cause.

Note that the detail message associated with - * cause is not automatically incorporated in + * {@code cause} is not automatically incorporated in * this throwable's detail message. * *

The {@link #fillInStackTrace()} method is called to initialize @@ -251,7 +251,7 @@ public class Throwable implements Serializable { * @param message the detail message (which is saved for later retrieval * by the {@link #getMessage()} method). * @param cause the cause (which is saved for later retrieval by the - * {@link #getCause()} method). (A null value is + * {@link #getCause()} method). (A {@code null} value is * permitted, and indicates that the cause is nonexistent or * unknown.) * @since 1.4 @@ -264,8 +264,8 @@ public class Throwable implements Serializable { /** * Constructs a new throwable with the specified cause and a detail - * message of (cause==null ? null : cause.toString()) (which - * typically contains the class and detail message of cause). + * message of {@code (cause==null ? null : cause.toString())} (which + * typically contains the class and detail message of {@code cause}). * This constructor is useful for throwables that are little more than * wrappers for other throwables (for example, {@link * java.security.PrivilegedActionException}). @@ -274,7 +274,7 @@ public class Throwable implements Serializable { * the stack trace data in the newly created throwable. * * @param cause the cause (which is saved for later retrieval by the - * {@link #getCause()} method). (A null value is + * {@link #getCause()} method). (A {@code null} value is * permitted, and indicates that the cause is nonexistent or * unknown.) * @since 1.4 @@ -288,8 +288,8 @@ public class Throwable implements Serializable { /** * Returns the detail message string of this throwable. * - * @return the detail message string of this Throwable instance - * (which may be null). + * @return the detail message string of this {@code Throwable} instance + * (which may be {@code null}). */ public String getMessage() { return detailMessage; @@ -300,7 +300,7 @@ public class Throwable implements Serializable { * Subclasses may override this method in order to produce a * locale-specific message. For subclasses that do not override this * method, the default implementation returns the same result as - * getMessage(). + * {@code getMessage()}. * * @return The localized description of this throwable. * @since JDK1.1 @@ -310,22 +310,22 @@ public class Throwable implements Serializable { } /** - * Returns the cause of this throwable or null if the + * Returns the cause of this throwable or {@code null} if the * cause is nonexistent or unknown. (The cause is the throwable that * caused this throwable to get thrown.) * *

This implementation returns the cause that was supplied via one of - * the constructors requiring a Throwable, or that was set after + * the constructors requiring a {@code Throwable}, or that was set after * creation with the {@link #initCause(Throwable)} method. While it is * typically unnecessary to override this method, a subclass can override * it to return a cause set by some other means. This is appropriate for * a "legacy chained throwable" that predates the addition of chained - * exceptions to Throwable. Note that it is not - * necessary to override any of the PrintStackTrace methods, - * all of which invoke the getCause method to determine the + * exceptions to {@code Throwable}. Note that it is not + * necessary to override any of the {@code PrintStackTrace} methods, + * all of which invoke the {@code getCause} method to determine the * cause of a throwable. * - * @return the cause of this throwable or null if the + * @return the cause of this throwable or {@code null} if the * cause is nonexistent or unknown. * @since 1.4 */ @@ -345,11 +345,11 @@ public class Throwable implements Serializable { * even once. * * @param cause the cause (which is saved for later retrieval by the - * {@link #getCause()} method). (A null value is + * {@link #getCause()} method). (A {@code null} value is * permitted, and indicates that the cause is nonexistent or * unknown.) - * @return a reference to this Throwable instance. - * @throws IllegalArgumentException if cause is this + * @return a reference to this {@code Throwable} instance. + * @throws IllegalArgumentException if {@code cause} is this * throwable. (A throwable cannot be its own cause.) * @throws IllegalStateException if this throwable was * created with {@link #Throwable(Throwable)} or @@ -375,7 +375,7 @@ public class Throwable implements Serializable { *

  • the result of invoking this object's {@link #getLocalizedMessage} * method * - * If getLocalizedMessage returns null, then just + * If {@code getLocalizedMessage} returns {@code null}, then just * the class name is returned. * * @return a string representation of this throwable. @@ -389,8 +389,8 @@ public class Throwable implements Serializable { /** * Prints this throwable and its backtrace to the * standard error stream. This method prints a stack trace for this - * Throwable object on the error output stream that is - * the value of the field System.err. The first line of + * {@code Throwable} object on the error output stream that is + * the value of the field {@code System.err}. The first line of * output contains the result of the {@link #toString()} method for * this object. Remaining lines represent data previously recorded by * the method {@link #fillInStackTrace()}. The format of this @@ -435,7 +435,7 @@ public class Throwable implements Serializable { * at Junk.c(Junk.java:21) * ... 3 more *
  • - * Note the presence of lines containing the characters "...". + * Note the presence of lines containing the characters {@code "..."}. * These lines indicate that the remainder of the stack trace for this * exception matches the indicated number of frames from the bottom of the * stack trace of the exception that was caused by this exception (the @@ -542,14 +542,17 @@ public class Throwable implements Serializable { /** * Prints this throwable and its backtrace to the specified print stream. * - * @param s PrintStream to use for output + * @param s {@code PrintStream} to use for output */ public void printStackTrace(PrintStream s) { printStackTrace(new WrappedPrintStream(s)); } private void printStackTrace(PrintStreamOrWriter s) { - Set dejaVu = new HashSet(); + // Guard against malicious overrides of Throwable.equals by + // using a Set with identity equality semantics. + Set dejaVu = + Collections.newSetFromMap(new IdentityHashMap()); dejaVu.add(this); synchronized (s.lock()) { @@ -616,7 +619,7 @@ public class Throwable implements Serializable { * Prints this throwable and its backtrace to the specified * print writer. * - * @param s PrintWriter to use for output + * @param s {@code PrintWriter} to use for output * @since JDK1.1 */ public void printStackTrace(PrintWriter s) { @@ -669,10 +672,10 @@ public class Throwable implements Serializable { /** * Fills in the execution stack trace. This method records within this - * Throwable object information about the current state of + * {@code Throwable} object information about the current state of * the stack frames for the current thread. * - * @return a reference to this Throwable instance. + * @return a reference to this {@code Throwable} instance. * @see java.lang.Throwable#printStackTrace() */ public synchronized native Throwable fillInStackTrace(); @@ -694,7 +697,7 @@ public class Throwable implements Serializable { * this throwable is permitted to return a zero-length array from this * method. Generally speaking, the array returned by this method will * contain one element for every frame that would be printed by - * printStackTrace. + * {@code printStackTrace}. * * @return an array of stack trace elements representing the stack trace * pertaining to this throwable. @@ -727,14 +730,14 @@ public class Throwable implements Serializable { * read from a serialization stream. * * @param stackTrace the stack trace elements to be associated with - * this Throwable. The specified array is copied by this + * this {@code Throwable}. The specified array is copied by this * call; changes in the specified array after the method invocation - * returns will have no affect on this Throwable's stack + * returns will have no affect on this {@code Throwable}'s stack * trace. * - * @throws NullPointerException if stackTrace is - * null, or if any of the elements of - * stackTrace are null + * @throws NullPointerException if {@code stackTrace} is + * {@code null}, or if any of the elements of + * {@code stackTrace} are {@code null} * * @since 1.4 */ @@ -761,8 +764,8 @@ public class Throwable implements Serializable { * package-protection for use by SharedSecrets. * * @param index index of the element to return. - * @throws IndexOutOfBoundsException if index < 0 || - * index >= getStackTraceDepth() + * @throws IndexOutOfBoundsException if {@code index < 0 || + * index >= getStackTraceDepth() } */ native StackTraceElement getStackTraceElement(int index); @@ -794,14 +797,27 @@ public class Throwable implements Serializable { * were suppressed, typically by the automatic resource management * statement, in order to deliver this exception. * + *

    Note that when one exception {@linkplain + * #initCause(Throwable) causes} another exception, the first + * exception is usually caught and then the second exception is + * thrown in response. In contrast, when one exception suppresses + * another, two exceptions are thrown in sibling code blocks, such + * as in a {@code try} block and in its {@code finally} block, and + * control flow can only continue with one exception so the second + * is recorded as a suppressed exception of the first. + * * @param exception the exception to be added to the list of * suppressed exceptions * @throws NullPointerException if {@code exception} is null + * @throws IllegalArgumentException if {@code exception} is this + * throwable; a throwable cannot suppress itself. * @since 1.7 */ public synchronized void addSuppressedException(Throwable exception) { if (exception == null) throw new NullPointerException(NULL_CAUSE_MESSAGE); + if (exception == this) + throw new IllegalArgumentException("Self-suppression not permitted"); if (suppressedExceptions.size() == 0) suppressedExceptions = new ArrayList(); diff --git a/test/java/lang/Throwable/SuppressedExceptions.java b/test/java/lang/Throwable/SuppressedExceptions.java index 89f974c0f4f0c0904edeeea653e0a0341b8453e7..0993cd6333f99429df9a79e6e13f0629418ed4c9 100644 --- a/test/java/lang/Throwable/SuppressedExceptions.java +++ b/test/java/lang/Throwable/SuppressedExceptions.java @@ -26,7 +26,7 @@ import java.util.*; /* * @test - * @bug 6911258 6962571 + * @bug 6911258 6962571 6963622 * @summary Basic tests of suppressed exceptions * @author Joseph D. Darcy */ @@ -35,11 +35,22 @@ public class SuppressedExceptions { private static String message = "Bad suppressed exception information"; public static void main(String... args) throws Exception { + noSelfSuppression(); basicSupressionTest(); serializationTest(); selfReference(); } + private static void noSelfSuppression() { + Throwable throwable = new Throwable(); + try { + throwable.addSuppressedException(throwable); + throw new RuntimeException("IllegalArgumentException for self-suppresion not thrown."); + } catch (IllegalArgumentException iae) { + ; // Expected + } + } + private static void basicSupressionTest() { Throwable throwable = new Throwable(); RuntimeException suppressed = new RuntimeException("A suppressed exception."); @@ -156,9 +167,8 @@ public class SuppressedExceptions { throwable1.printStackTrace(); - - throwable1.addSuppressedException(throwable1); throwable1.addSuppressedException(throwable2); + throwable2.addSuppressedException(throwable1); throwable1.printStackTrace(); }