| /* |
| * Copyright (c) 1998, 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 4026895 |
| @summary Ensure that System.runFinalization does not run finalizers in the |
| thread that invokes it |
| */ |
| |
| |
| public class FinThreads { |
| |
| static Thread mainThread; |
| |
| static Object lock = new Object(); /* Protects following two fields */ |
| static Thread finalizerThread = null; |
| static Thread finalizedBy = null; |
| |
| |
| static class Foo { |
| |
| boolean catchFinalizer = false; |
| |
| /* Instances are only created in an auxiliary thread, in order to |
| guard against stray references from the current thread's stack |
| */ |
| static public void create(final boolean catchFinalizer) |
| throws InterruptedException |
| { |
| Thread t = new Thread(new Runnable() { |
| public void run() { |
| new Foo(catchFinalizer); |
| }}); |
| t.start(); |
| t.join(); |
| } |
| |
| public Foo(boolean catchFinalizer) { |
| this.catchFinalizer = catchFinalizer; |
| } |
| |
| public void finalize() throws InterruptedException { |
| if (catchFinalizer) { |
| boolean gotFinalizer = false; |
| synchronized (lock) { |
| if (finalizerThread == null) { |
| finalizerThread = Thread.currentThread(); |
| gotFinalizer = true; |
| } |
| } |
| if (gotFinalizer) { |
| System.err.println("Caught finalizer thread; sleeping..."); |
| Thread.sleep(Long.MAX_VALUE); |
| } |
| } else { |
| synchronized (lock) { |
| finalizedBy = Thread.currentThread(); |
| } |
| System.err.println("Test object finalized by " + finalizedBy); |
| } |
| } |
| |
| } |
| |
| |
| static void alarm(final Thread sleeper, final long delay) |
| throws InterruptedException |
| { |
| Thread t = new Thread(new Runnable() { |
| public void run() { |
| try { |
| Thread.sleep(delay); |
| System.err.println("Waking " + sleeper); |
| sleeper.interrupt(); |
| } catch (InterruptedException x) { } |
| }}); |
| t.setDaemon(true); |
| t.start(); |
| } |
| |
| |
| public static void main(String[] args) throws Exception { |
| |
| mainThread = Thread.currentThread(); |
| |
| /* Find the finalizer thread and put it to sleep */ |
| for (;;) { |
| Foo.create(true); |
| System.gc(); |
| synchronized (lock) { |
| if (finalizerThread != null) break; |
| } |
| } |
| |
| /* Now create a finalizable object and run finalization */ |
| alarm(finalizerThread, 5000); |
| Foo.create(false); |
| for (;;) { |
| System.gc(); |
| System.runFinalization(); |
| synchronized (lock) { |
| if (finalizedBy != null) break; |
| } |
| } |
| |
| if (finalizedBy == mainThread) |
| throw new Exception("Finalizer run in main thread"); |
| |
| } |
| |
| } |