Throwable
class is the superclass of all errors and
@@ -102,7 +103,7 @@
* lowLevelOp();
* } catch (LowLevelException le) {
* throw (HighLevelException)
- new HighLevelException().initCause(le); // Legacy constructor
+ * new HighLevelException().initCause(le); // Legacy constructor
* }
*
*
@@ -193,6 +194,21 @@
*/
/**
+ * The list of suppressed exceptions, as returned by
+ * {@link #getSuppressedExceptions()}.
+ *
+ * @serial
+ * @since 1.7
+ */
+ private Listnull
as its detail message.
* The cause is not initialized, and may subsequently be initialized by a
* call to {@link #initCause}.
@@ -469,6 +485,52 @@
* class LowLevelException extends Exception {
* }
*
+ * As of release 7, the platform supports the notion of
+ * suppressed exceptions (in conjunction with automatic
+ * resource management blocks). Any exceptions that were
+ * suppressed in order to deliver an exception are printed out
+ * beneath the stack trace. The format of this information
+ * depends on the implementation, but the following example may be
+ * regarded as typical:
+ *
+ * + * Exception in thread "main" java.lang.Exception: Something happened + * at Foo.bar(Foo.java:10) + * at Foo.main(Foo.java:5) + * Suppressed: Resource$CloseFailException: Resource ID = 0 + * at Resource.close(Resource.java:26) + * at Foo.bar(Foo.java:9) + * ... 1 more + *+ * Note that the "... n more" notation is used on suppressed exceptions + * just at it is used on causes. Unlike causes, suppressed exceptions are + * indented beyond their "containing exceptions." + * + *
An exception can have both a cause and one or more suppressed + * exceptions: + *
+ * Exception in thread "main" java.lang.Exception: Main block + * at Foo3.main(Foo3.java:7) + * Suppressed: Resource$CloseFailException: Resource ID = 2 + * at Resource.close(Resource.java:26) + * at Foo3.main(Foo3.java:5) + * Suppressed: Resource$CloseFailException: Resource ID = 1 + * at Resource.close(Resource.java:26) + * at Foo3.main(Foo3.java:5) + * Caused by: java.lang.Exception: I did it + * at Foo3.main(Foo3.java:8) + *+ * Likewise, a suppressed exception can have a cause: + *
+ * Exception in thread "main" java.lang.Exception: Main block + * at Foo4.main(Foo4.java:6) + * Suppressed: Resource2$CloseFailException: Resource ID = 1 + * at Resource2.close(Resource2.java:20) + * at Foo4.main(Foo4.java:5) + * Caused by: java.lang.Exception: Rats, you caught me + * at Resource2$CloseFailException.*/ public void printStackTrace() { printStackTrace(System.err); @@ -480,44 +542,60 @@ * @param s(Resource2.java:45) + * ... 2 more + *
PrintStream
to use for output
*/
public void printStackTrace(PrintStream s) {
- synchronized (s) {
+ printStackTrace(new WrappedPrintStream(s));
+ }
+
+ private void printStackTrace(PrintStreamOrWriter s) {
+ synchronized (s.lock()) {
+ // Print our stack trace
s.println(this);
StackTraceElement[] trace = getOurStackTrace();
- for (int i=0; i < trace.length; i++)
- s.println("\tat " + trace[i]);
+ for (StackTraceElement traceElement : trace)
+ s.println("\tat " + traceElement);
+
+ // Print suppressed exceptions, if any
+ for (Throwable se : suppressedExceptions)
+ se.printEnclosedStackTrace(s, trace, SUPPRESSED_CAPTION, "\t");
+ // Print cause, if any
Throwable ourCause = getCause();
if (ourCause != null)
- ourCause.printStackTraceAsCause(s, trace);
+ ourCause.printEnclosedStackTrace(s, trace, CAUSE_CAPTION, "");
}
}
/**
- * Print our stack trace as a cause for the specified stack trace.
+ * Print our stack trace as an enclosed exception for the specified
+ * stack trace.
*/
- private void printStackTraceAsCause(PrintStream s,
- StackTraceElement[] causedTrace)
- {
- // assert Thread.holdsLock(s);
+ private void printEnclosedStackTrace(PrintStreamOrWriter s,
+ StackTraceElement[] enclosingTrace, String caption, String prefix) {
+ assert Thread.holdsLock(s.lock());
- // Compute number of frames in common between this and caused
+ // Compute number of frames in common between this and enclosing trace
StackTraceElement[] trace = getOurStackTrace();
- int m = trace.length-1, n = causedTrace.length-1;
- while (m >= 0 && n >=0 && trace[m].equals(causedTrace[n])) {
+ int m = trace.length-1, n = enclosingTrace.length-1;
+ while (m >= 0 && n >=0 && trace[m].equals(enclosingTrace[n])) {
m--; n--;
}
int framesInCommon = trace.length - 1 - m;
- s.println("Caused by: " + this);
- for (int i=0; i <= m; i++)
- s.println("\tat " + trace[i]);
+ // Print our stack trace
+ s.println(prefix + caption + this);
+ for (int i = 0; i <= m; i++)
+ s.println(prefix + "\tat " + trace[i]);
if (framesInCommon != 0)
- s.println("\t... " + framesInCommon + " more");
+ s.println(prefix + "\t... " + framesInCommon + " more");
+
+ // Print suppressed exceptions, if any
+ for (Throwable se : suppressedExceptions)
+ se.printEnclosedStackTrace(s, trace, SUPPRESSED_CAPTION,
+ prefix +"\t");
- // Recurse if we have a cause
+ // Print cause, if any
Throwable ourCause = getCause();
if (ourCause != null)
- ourCause.printStackTraceAsCause(s, trace);
+ ourCause.printEnclosedStackTrace(s, trace, CAUSE_CAPTION, prefix);
}
/**
@@ -528,44 +606,51 @@
* @since JDK1.1
*/
public void printStackTrace(PrintWriter s) {
- synchronized (s) {
- s.println(this);
- StackTraceElement[] trace = getOurStackTrace();
- for (int i=0; i < trace.length; i++)
- s.println("\tat " + trace[i]);
-
- Throwable ourCause = getCause();
- if (ourCause != null)
- ourCause.printStackTraceAsCause(s, trace);
- }
+ printStackTrace(new WrappedPrintWriter(s));
}
/**
- * Print our stack trace as a cause for the specified stack trace.
+ * Wrapper class for PrintStream and PrintWirter to enable a single
+ * implementation of printStackTrace.
*/
- private void printStackTraceAsCause(PrintWriter s,
- StackTraceElement[] causedTrace)
- {
- // assert Thread.holdsLock(s);
+ private abstract static class PrintStreamOrWriter {
+ /** Returns the object to be locked when using this StreamOrWriter */
+ abstract Object lock();
- // Compute number of frames in common between this and caused
- StackTraceElement[] trace = getOurStackTrace();
- int m = trace.length-1, n = causedTrace.length-1;
- while (m >= 0 && n >=0 && trace[m].equals(causedTrace[n])) {
- m--; n--;
+ /** Prints the specified string as a line on this StreamOrWriter */
+ abstract void println(Object o);
+ }
+
+ private static class WrappedPrintStream extends PrintStreamOrWriter {
+ private final PrintStream printStream;
+
+ WrappedPrintStream(PrintStream printStream) {
+ this.printStream = printStream;
}
- int framesInCommon = trace.length - 1 - m;
- s.println("Caused by: " + this);
- for (int i=0; i <= m; i++)
- s.println("\tat " + trace[i]);
- if (framesInCommon != 0)
- s.println("\t... " + framesInCommon + " more");
+ Object lock() {
+ return printStream;
+ }
- // Recurse if we have a cause
- Throwable ourCause = getCause();
- if (ourCause != null)
- ourCause.printStackTraceAsCause(s, trace);
+ void println(Object o) {
+ printStream.println(o);
+ }
+ }
+
+ private static class WrappedPrintWriter extends PrintStreamOrWriter {
+ private final PrintWriter printWriter;
+
+ WrappedPrintWriter(PrintWriter printWriter) {
+ this.printWriter = printWriter;
+ }
+
+ Object lock() {
+ return printWriter;
+ }
+
+ void println(Object o) {
+ printWriter.println(o);
+ }
}
/**
@@ -667,10 +752,58 @@
*/
native StackTraceElement getStackTraceElement(int index);
+ private void readObject(java.io.ObjectInputStream s)
+ throws java.io.IOException, ClassNotFoundException {
+ s.defaultReadObject(); // read in all fields
+ ListClasses implementing this method are strongly encouraged to + * be declared to throw more specific exceptions (or no exception + * at all, if the close cannot fail). + * + * @throws Exception if this resource cannot be closed + */ + void close() throws Exception; +} --- /dev/null 2009-08-12 17:12:33.000000000 -0700 +++ new/jdk/test/java/lang/Throwable/SuppressedExceptions.java 2010-06-17 20:29:17.000000000 -0700 @@ -0,0 +1,149 @@ +/* + * Copyright (c) 2010, 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. + */ + +import java.io.*; +import java.util.*; + +/* + * @test + * @bug 6911258 + * @summary Basic tests of suppressed exceptions + * @author Joseph D. Darcy + */ + +public class SuppressedExceptions { + private static String message = "Bad suppressed exception information"; + + public static void main(String... args) throws Exception { + basicSupressionTest(); + serializationTest(); + } + + private static void basicSupressionTest() { + Throwable throwable = new Throwable(); + RuntimeException suppressed = new RuntimeException("A suppressed exception."); + AssertionError repressed = new AssertionError("A repressed error."); + + Throwable[] t0 = throwable.getSuppressedExceptions(); + if (t0.length != 0) { + throw new RuntimeException(message); + } + throwable.printStackTrace(); + + throwable.addSuppressedException(suppressed); + Throwable[] t1 = throwable.getSuppressedExceptions(); + if (t1.length != 1 || + t1[0] != suppressed) {throw new RuntimeException(message); + } + throwable.printStackTrace(); + + throwable.addSuppressedException(repressed); + Throwable[] t2 = throwable.getSuppressedExceptions(); + if (t2.length != 2 || + t2[0] != suppressed || + t2[1] != repressed) { + throw new RuntimeException(message); + } + throwable.printStackTrace(); + } + + private static void serializationTest() throws Exception { + /* + * Bytes of the serial form of + * + * (new Throwable())setStackTrace(new StackTraceElement[0]) + * + * from JDK 6; suppressedException field will be missing and + * thus default to null upon deserialization. + */ + byte[] bytes = { + (byte)0xac, (byte)0xed, (byte)0x00, (byte)0x05, (byte)0x73, (byte)0x72, (byte)0x00, (byte)0x13, + (byte)0x6a, (byte)0x61, (byte)0x76, (byte)0x61, (byte)0x2e, (byte)0x6c, (byte)0x61, (byte)0x6e, + (byte)0x67, (byte)0x2e, (byte)0x54, (byte)0x68, (byte)0x72, (byte)0x6f, (byte)0x77, (byte)0x61, + (byte)0x62, (byte)0x6c, (byte)0x65, (byte)0xd5, (byte)0xc6, (byte)0x35, (byte)0x27, (byte)0x39, + (byte)0x77, (byte)0xb8, (byte)0xcb, (byte)0x03, (byte)0x00, (byte)0x03, (byte)0x4c, (byte)0x00, + (byte)0x05, (byte)0x63, (byte)0x61, (byte)0x75, (byte)0x73, (byte)0x65, (byte)0x74, (byte)0x00, + (byte)0x15, (byte)0x4c, (byte)0x6a, (byte)0x61, (byte)0x76, (byte)0x61, (byte)0x2f, (byte)0x6c, + (byte)0x61, (byte)0x6e, (byte)0x67, (byte)0x2f, (byte)0x54, (byte)0x68, (byte)0x72, (byte)0x6f, + (byte)0x77, (byte)0x61, (byte)0x62, (byte)0x6c, (byte)0x65, (byte)0x3b, (byte)0x4c, (byte)0x00, + (byte)0x0d, (byte)0x64, (byte)0x65, (byte)0x74, (byte)0x61, (byte)0x69, (byte)0x6c, (byte)0x4d, + (byte)0x65, (byte)0x73, (byte)0x73, (byte)0x61, (byte)0x67, (byte)0x65, (byte)0x74, (byte)0x00, + (byte)0x12, (byte)0x4c, (byte)0x6a, (byte)0x61, (byte)0x76, (byte)0x61, (byte)0x2f, (byte)0x6c, + (byte)0x61, (byte)0x6e, (byte)0x67, (byte)0x2f, (byte)0x53, (byte)0x74, (byte)0x72, (byte)0x69, + (byte)0x6e, (byte)0x67, (byte)0x3b, (byte)0x5b, (byte)0x00, (byte)0x0a, (byte)0x73, (byte)0x74, + (byte)0x61, (byte)0x63, (byte)0x6b, (byte)0x54, (byte)0x72, (byte)0x61, (byte)0x63, (byte)0x65, + (byte)0x74, (byte)0x00, (byte)0x1e, (byte)0x5b, (byte)0x4c, (byte)0x6a, (byte)0x61, (byte)0x76, + (byte)0x61, (byte)0x2f, (byte)0x6c, (byte)0x61, (byte)0x6e, (byte)0x67, (byte)0x2f, (byte)0x53, + (byte)0x74, (byte)0x61, (byte)0x63, (byte)0x6b, (byte)0x54, (byte)0x72, (byte)0x61, (byte)0x63, + (byte)0x65, (byte)0x45, (byte)0x6c, (byte)0x65, (byte)0x6d, (byte)0x65, (byte)0x6e, (byte)0x74, + (byte)0x3b, (byte)0x78, (byte)0x70, (byte)0x71, (byte)0x00, (byte)0x7e, (byte)0x00, (byte)0x04, + (byte)0x70, (byte)0x75, (byte)0x72, (byte)0x00, (byte)0x1e, (byte)0x5b, (byte)0x4c, (byte)0x6a, + (byte)0x61, (byte)0x76, (byte)0x61, (byte)0x2e, (byte)0x6c, (byte)0x61, (byte)0x6e, (byte)0x67, + (byte)0x2e, (byte)0x53, (byte)0x74, (byte)0x61, (byte)0x63, (byte)0x6b, (byte)0x54, (byte)0x72, + (byte)0x61, (byte)0x63, (byte)0x65, (byte)0x45, (byte)0x6c, (byte)0x65, (byte)0x6d, (byte)0x65, + (byte)0x6e, (byte)0x74, (byte)0x3b, (byte)0x02, (byte)0x46, (byte)0x2a, (byte)0x3c, (byte)0x3c, + (byte)0xfd, (byte)0x22, (byte)0x39, (byte)0x02, (byte)0x00, (byte)0x00, (byte)0x78, (byte)0x70, + (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x78, (byte)0xac, (byte)0xed, (byte)0x00, + (byte)0x05, (byte)0x73, (byte)0x72, (byte)0x00, (byte)0x13, (byte)0x6a, (byte)0x61, (byte)0x76, + (byte)0x61, (byte)0x2e, (byte)0x6c, (byte)0x61, (byte)0x6e, (byte)0x67, (byte)0x2e, (byte)0x54, + (byte)0x68, (byte)0x72, (byte)0x6f, (byte)0x77, (byte)0x61, (byte)0x62, (byte)0x6c, (byte)0x65, + (byte)0xd5, (byte)0xc6, (byte)0x35, (byte)0x27, (byte)0x39, (byte)0x77, (byte)0xb8, (byte)0xcb, + (byte)0x03, (byte)0x00, (byte)0x03, (byte)0x4c, (byte)0x00, (byte)0x05, (byte)0x63, (byte)0x61, + (byte)0x75, (byte)0x73, (byte)0x65, (byte)0x74, (byte)0x00, (byte)0x15, (byte)0x4c, (byte)0x6a, + (byte)0x61, (byte)0x76, (byte)0x61, (byte)0x2f, (byte)0x6c, (byte)0x61, (byte)0x6e, (byte)0x67, + (byte)0x2f, (byte)0x54, (byte)0x68, (byte)0x72, (byte)0x6f, (byte)0x77, (byte)0x61, (byte)0x62, + (byte)0x6c, (byte)0x65, (byte)0x3b, (byte)0x4c, (byte)0x00, (byte)0x0d, (byte)0x64, (byte)0x65, + (byte)0x74, (byte)0x61, (byte)0x69, (byte)0x6c, (byte)0x4d, (byte)0x65, (byte)0x73, (byte)0x73, + (byte)0x61, (byte)0x67, (byte)0x65, (byte)0x74, (byte)0x00, (byte)0x12, (byte)0x4c, (byte)0x6a, + (byte)0x61, (byte)0x76, (byte)0x61, (byte)0x2f, (byte)0x6c, (byte)0x6e, (byte)0x67, (byte)0x3b, + (byte)0x61, (byte)0x6e, (byte)0x67, (byte)0x2f, (byte)0x53, (byte)0x74, (byte)0x72, (byte)0x69, + (byte)0x5b, (byte)0x00, (byte)0x0a, (byte)0x73, (byte)0x74, (byte)0x61, (byte)0x63, (byte)0x6b, + (byte)0x54, (byte)0x72, (byte)0x61, (byte)0x63, (byte)0x65, (byte)0x74, (byte)0x00, (byte)0x1e, + (byte)0x5b, (byte)0x4c, (byte)0x6a, (byte)0x61, (byte)0x76, (byte)0x61, (byte)0x2f, (byte)0x6c, + (byte)0x61, (byte)0x6e, (byte)0x67, (byte)0x2f, (byte)0x53, (byte)0x74, (byte)0x61, (byte)0x63, + (byte)0x6b, (byte)0x54, (byte)0x72, (byte)0x61, (byte)0x63, (byte)0x65, (byte)0x45, (byte)0x6c, + (byte)0x65, (byte)0x6d, (byte)0x65, (byte)0x6e, (byte)0x74, (byte)0x3b, (byte)0x78, (byte)0x70, + (byte)0x71, (byte)0x00, (byte)0x7e, (byte)0x00, (byte)0x04, (byte)0x70, (byte)0x75, (byte)0x72, + (byte)0x00, (byte)0x1e, (byte)0x5b, (byte)0x4c, (byte)0x6a, (byte)0x61, (byte)0x76, (byte)0x61, + (byte)0x2e, (byte)0x6c, (byte)0x61, (byte)0x6e, (byte)0x67, (byte)0x2e, (byte)0x53, (byte)0x74, + (byte)0x61, (byte)0x63, (byte)0x6b, (byte)0x54, (byte)0x72, (byte)0x61, (byte)0x63, (byte)0x65, + (byte)0x45, (byte)0x6c, (byte)0x65, (byte)0x6d, (byte)0x65, (byte)0x6e, (byte)0x74, (byte)0x3b, + (byte)0x02, (byte)0x46, (byte)0x2a, (byte)0x3c, (byte)0x3c, (byte)0xfd, (byte)0x22, (byte)0x39, + (byte)0x02, (byte)0x00, (byte)0x00, (byte)0x78, (byte)0x70, + }; + + ByteArrayInputStream bais = new ByteArrayInputStream(bytes); + ObjectInputStream ois = new ObjectInputStream(bais); + + Object o = ois.readObject(); + Throwable throwable = (Throwable) o; + + System.err.println("TESTING SERIALIZED EXCEPTION"); + + Throwable[] t0 = throwable.getSuppressedExceptions(); + if (t0.length != 0) { // Will fail if t0 is null. + throw new RuntimeException(message); + } + throwable.printStackTrace(); + } +}