--- old/src/share/classes/java/lang/ref/ReferenceQueue.java 2014-02-27 01:57:21.784373627 +0400 +++ new/src/share/classes/java/lang/ref/ReferenceQueue.java 2014-02-27 01:57:20.844385444 +0400 @@ -138,11 +138,17 @@ synchronized (lock) { Reference r = reallyPoll(); if (r != null) return r; + long start = (timeout == 0) ? 0 : System.nanoTime(); for (;;) { lock.wait(timeout); r = reallyPoll(); if (r != null) return r; - if (timeout != 0) return null; + if (timeout != 0) { + long end = System.nanoTime(); + timeout -= (end - start) / 1000_000; + if (timeout <= 0) return null; + start = end; + } } } } --- /dev/null 2014-02-26 09:32:43.186606359 +0400 +++ new/test/java/lang/ref/EarlyTimeout.java 2014-02-27 01:57:22.588363519 +0400 @@ -0,0 +1,100 @@ +/* + * Copyright (c) 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. + */ + +/* @test + * @bug 6853696 + * @summary ReferenceQueue#remove(timeout) should not return null before + * timeout is elapsed + */ + +import java.lang.InterruptedException; +import java.lang.System; +import java.lang.ref.Reference; +import java.lang.ref.ReferenceQueue; +import java.lang.ref.WeakReference; +import java.util.concurrent.CountDownLatch; + +/** + * In order to demonstrate the issue we make several threads (two appears to be sufficient) + * to block in ReferenceQueue#remove(timeout) at the same time. + * Then, we force a reference to be enqueued by setting its referent to null and calling System.gs(). + * One of the threads gets the reference returned from the remove(). + * The other threads get null: + * 1) with bug: this may happen before the specified timeout is elapsed, + * 2) without bug: this can only happen after the timeout is fully elapsed. + */ + +public class EarlyTimeout extends Thread { + + static final int THREADS_COUNT = 2; + static final int TIMEOUT = 1000; + + static Object referent = new Object(); + static final ReferenceQueue queue = new ReferenceQueue(); + static final WeakReference weakReference = new WeakReference(referent, queue); + static final CountDownLatch startedSignal = new CountDownLatch(THREADS_COUNT); + + long actual; + Reference reference; + + public static void main(String[] args) throws Exception { + EarlyTimeout[] threads = new EarlyTimeout[THREADS_COUNT]; + for (int i = 0; i < THREADS_COUNT; ++i) { + threads[i] = new EarlyTimeout(); + threads[i].start(); + } + startedSignal.await(); + referent = null; + System.gc(); + for (EarlyTimeout thread : threads) { + thread.join(); + } + if (weakReference.get() != null) { + throw new RuntimeException("weakReference was not cleared"); + } + int nonNullRefCount = 0; + for (EarlyTimeout thread : threads) { + if (thread.reference == null && thread.actual < TIMEOUT) { + throw new RuntimeException("elapsed time " + thread.actual + + " is less than timeout " + TIMEOUT); + } + if (thread.reference != null) { + nonNullRefCount++; + } + } + if (nonNullRefCount != 1) { + throw new RuntimeException("more than one references were removed from queue"); + } + } + + public void run() { + try { + startedSignal.countDown(); + long start = System.currentTimeMillis(); + reference = queue.remove(TIMEOUT); + actual = System.currentTimeMillis() - start; + } catch (InterruptedException ex) { + throw new RuntimeException(ex); + } + } +}