6730507: java.util.Timer schedule delay Long.MAX_VALUE causes task to execute multiple times
Reviewed-by: chegar
--- a/jdk/src/share/classes/java/util/Timer.java Wed Aug 06 10:49:31 2008 -0700
+++ b/jdk/src/share/classes/java/util/Timer.java Thu Aug 07 06:36:41 2008 -0700
@@ -93,12 +93,12 @@
* and the timer thread consumes, executing timer tasks as appropriate,
* and removing them from the queue when they're obsolete.
*/
- private TaskQueue queue = new TaskQueue();
+ private final TaskQueue queue = new TaskQueue();
/**
* The timer thread.
*/
- private TimerThread thread = new TimerThread(queue);
+ private final TimerThread thread = new TimerThread(queue);
/**
* This object causes the timer's task execution thread to exit
@@ -107,7 +107,7 @@
* Timer as such a finalizer would be susceptible to a subclass's
* finalizer forgetting to call it.
*/
- private Object threadReaper = new Object() {
+ private final Object threadReaper = new Object() {
protected void finalize() throws Throwable {
synchronized(queue) {
thread.newTasksMayBeScheduled = false;
@@ -119,7 +119,7 @@
/**
* This ID is used to generate thread names.
*/
- private static AtomicInteger nextSerialNumber = new AtomicInteger(0);
+ private final static AtomicInteger nextSerialNumber = new AtomicInteger(0);
private static int serialNumber() {
return nextSerialNumber.getAndIncrement();
}
@@ -387,6 +387,11 @@
if (time < 0)
throw new IllegalArgumentException("Illegal execution time.");
+ // Constrain value of period sufficiently to prevent numeric
+ // overflow while still being effectively infinitely large.
+ if (Math.abs(period) > (Long.MAX_VALUE >> 1))
+ period >>= 1;
+
synchronized(queue) {
if (!thread.newTasksMayBeScheduled)
throw new IllegalStateException("Timer already cancelled.");
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/Timer/DelayOverflow.java Thu Aug 07 06:36:41 2008 -0700
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * @test
+ * @bug 6730507
+ * @summary java.util.Timer schedule delay Long.MAX_VALUE causes task to execute multiple times
+ * @author Chris Hegarty
+ * @author Martin Buchholz
+ */
+
+import java.util.Date;
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class DelayOverflow
+{
+ void scheduleNow(Timer timer, TimerTask task, int how) {
+ switch (how) {
+ case 0 :
+ timer.schedule(task, new Date(), Long.MAX_VALUE);
+ break;
+ case 1:
+ timer.schedule(task, 0L, Long.MAX_VALUE);
+ break;
+ case 2:
+ timer.scheduleAtFixedRate(task, new Date(), Long.MAX_VALUE);
+ break;
+ case 3:
+ timer.scheduleAtFixedRate(task, 0L, Long.MAX_VALUE);
+ break;
+ default:
+ fail(String.valueOf(how));
+ }
+ }
+
+ void sleep(long millis) {
+ try { Thread.sleep(millis); }
+ catch (Throwable t) { unexpected(t); }
+ }
+
+ /** Checks that scheduledExecutionTime returns a "recent" time. */
+ void checkScheduledExecutionTime(TimerTask task) {
+ long t = System.currentTimeMillis()
+ - task.scheduledExecutionTime();
+ check(t >= 0 && t < 1000 * 600);
+ }
+
+ void test(String[] args) throws Throwable {
+ for (int how=0; how<4; how++) {
+ final CountDownLatch done = new CountDownLatch(1);
+ final AtomicInteger count = new AtomicInteger(0);
+ final Timer timer = new Timer();
+ final TimerTask task = new TimerTask() {
+ @Override
+ public void run() {
+ checkScheduledExecutionTime(this);
+ count.incrementAndGet();
+ done.countDown();
+ }};
+
+ scheduleNow(timer, task, how);
+ done.await();
+ equal(count.get(), 1);
+ checkScheduledExecutionTime(task);
+ if (new java.util.Random().nextBoolean())
+ sleep(10);
+ check(task.cancel());
+ timer.cancel();
+ checkScheduledExecutionTime(task);
+ }
+ }
+
+ //--------------------- Infrastructure ---------------------------
+ volatile int passed = 0, failed = 0;
+ void pass() {passed++;}
+ void fail() {failed++; Thread.dumpStack();}
+ void fail(String msg) {System.err.println(msg); fail();}
+ void unexpected(Throwable t) {failed++; t.printStackTrace();}
+ void check(boolean cond) {if (cond) pass(); else fail();}
+ void equal(Object x, Object y) {
+ if (x == null ? y == null : x.equals(y)) pass();
+ else fail(x + " not equal to " + y);}
+ public static void main(String[] args) throws Throwable {
+ Class<?> k = new Object(){}.getClass().getEnclosingClass();
+ try {k.getMethod("instanceMain",String[].class)
+ .invoke( k.newInstance(), (Object) args);}
+ catch (Throwable e) {throw e.getCause();}}
+ public void instanceMain(String[] args) throws Throwable {
+ try {test(args);} catch (Throwable t) {unexpected(t);}
+ System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
+ if (failed > 0) throw new AssertionError("Some tests failed");}
+}