| /* |
| * Copyright (c) 2004, 2005, 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 5093922 2120055 |
| * @summary Test that NotificationBroadcasterSupport can be subclassed |
| * and used with synchronized(this) without causing deadlock |
| * @author Eamonn McManus |
| * @run clean BroadcasterSupportDeadlockTest |
| * @run build BroadcasterSupportDeadlockTest |
| * @run main BroadcasterSupportDeadlockTest |
| */ |
| |
| import java.lang.management.*; |
| import java.util.concurrent.*; |
| import javax.management.*; |
| |
| public class BroadcasterSupportDeadlockTest { |
| public static void main(String[] args) throws Exception { |
| try { |
| Class.forName(ManagementFactory.class.getName()); |
| } catch (Throwable t) { |
| System.out.println("TEST CANNOT RUN: needs JDK 5 at least"); |
| return; |
| } |
| |
| final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer(); |
| final BroadcasterMBean mbean = new Broadcaster(); |
| final ObjectName name = new ObjectName("test:type=Broadcaster"); |
| mbs.registerMBean(mbean, name); |
| |
| ThreadMXBean threads = ManagementFactory.getThreadMXBean(); |
| threads.setThreadContentionMonitoringEnabled(true); |
| |
| final Semaphore semaphore = new Semaphore(0); |
| |
| // Thread 1 - block the Broadcaster |
| Thread t1 = new Thread() { |
| public void run() { |
| try { |
| mbs.invoke(name, "block", |
| new Object[] {semaphore}, |
| new String[] {Semaphore.class.getName()}); |
| } catch (Exception e) { |
| e.printStackTrace(System.out); |
| } finally { |
| System.out.println("TEST INCORRECT: block returned"); |
| System.exit(1); |
| } |
| } |
| }; |
| t1.setDaemon(true); |
| t1.start(); |
| |
| /* Wait for Thread 1 to be doing Object.wait(). It's very |
| difficult to synchronize properly here so we wait for the |
| semaphore, then wait a little longer for the mbs.invoke to |
| run, then just in case that isn't enough, we wait for the |
| thread to be in WAITING state. This isn't foolproof, |
| because the machine could be very slow and the |
| Thread.getState() could find the thread in WAITING state |
| due to some operation it does on its way to the one we're |
| interested in. */ |
| semaphore.acquire(); |
| Thread.sleep(100); |
| while (t1.getState() != Thread.State.WAITING) |
| Thread.sleep(1); |
| |
| // Thread 2 - try to add a listener |
| final NotificationListener listener = new NotificationListener() { |
| public void handleNotification(Notification n, Object h) {} |
| }; |
| Thread t2 = new Thread() { |
| public void run() { |
| try { |
| mbs.addNotificationListener(name, listener, null, null); |
| } catch (Exception e) { |
| System.out.println("TEST INCORRECT: addNL failed:"); |
| e.printStackTrace(System.out); |
| } |
| } |
| }; |
| t2.setDaemon(true); |
| t2.start(); |
| |
| /* Wait for Thread 2 to be blocked on the monitor or to |
| succeed. */ |
| Thread.sleep(100); |
| |
| for (int i = 0; i < 1000/*ms*/; i++) { |
| t2.join(1/*ms*/); |
| switch (t2.getState()) { |
| case TERMINATED: |
| System.out.println("TEST PASSED"); |
| return; |
| case BLOCKED: |
| java.util.Map<Thread,StackTraceElement[]> traces = |
| Thread.getAllStackTraces(); |
| showStackTrace("Thread 1", traces.get(t1)); |
| showStackTrace("Thread 2", traces.get(t2)); |
| System.out.println("TEST FAILED: deadlock"); |
| System.exit(1); |
| break; |
| default: |
| break; |
| } |
| } |
| |
| System.out.println("TEST FAILED BUT DID NOT NOTICE DEADLOCK"); |
| Thread.sleep(10000); |
| System.exit(1); |
| } |
| |
| private static void showStackTrace(String title, |
| StackTraceElement[] stack) { |
| System.out.println("---" + title + "---"); |
| if (stack == null) |
| System.out.println("<no stack trace???>"); |
| else { |
| for (StackTraceElement elmt : stack) |
| System.out.println(" " + elmt); |
| } |
| System.out.println(); |
| } |
| |
| public static interface BroadcasterMBean { |
| public void block(Semaphore semaphore); |
| } |
| |
| public static class Broadcaster |
| extends NotificationBroadcasterSupport |
| implements BroadcasterMBean { |
| public synchronized void block(Semaphore semaphore) { |
| Object lock = new Object(); |
| synchronized (lock) { |
| try { |
| // Let the caller know that it can now wait for us to |
| // hit the WAITING state |
| semaphore.release(); |
| lock.wait(); // block forever |
| } catch (InterruptedException e) { |
| System.out.println("TEST INCORRECT: lock interrupted:"); |
| e.printStackTrace(System.out); |
| System.exit(1); |
| } |
| } |
| } |
| } |
| } |