| /* |
| * Copyright (c) 2005, 2015, 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 6318664 |
| * @summary Test deadlock in MBeanRegistration.preDeregister method |
| * @author Eamonn McManus |
| * |
| * @run clean PreDeregisterDeadlockTest |
| * @run build PreDeregisterDeadlockTest |
| * @run main PreDeregisterDeadlockTest |
| */ |
| |
| import java.util.concurrent.*; |
| import javax.management.*; |
| |
| public class PreDeregisterDeadlockTest { |
| public static interface BlibbyMBean {} |
| |
| public static class Blibby implements BlibbyMBean, MBeanRegistration { |
| public Blibby(MBeanServer mbs, ObjectName otherName) { |
| this.mbs = mbs; |
| this.otherName = otherName; |
| } |
| |
| public ObjectName preRegister(MBeanServer mbs, ObjectName on) { |
| return on; |
| } |
| |
| public void postRegister(Boolean done) {} |
| |
| public void preDeregister() { |
| if (otherName == null) |
| return; |
| try { |
| Thread t = new Thread() { |
| public void run() { |
| try { |
| mbs.unregisterMBean(otherName); |
| } catch (Throwable e) { |
| e.printStackTrace(System.out); |
| fail(e.toString()); |
| } |
| } |
| }; |
| t.start(); |
| t.join(5000L); |
| if (t.isAlive()) |
| fail("Deadlock detected"); |
| } catch (Throwable e) { |
| e.printStackTrace(System.out); |
| fail(e.toString()); |
| } |
| } |
| |
| public void postDeregister() {} |
| |
| private final MBeanServer mbs; |
| private final ObjectName otherName; |
| } |
| |
| public static interface BlobbyMBean {} |
| |
| public static class Blobby implements BlobbyMBean, MBeanRegistration { |
| public Blobby(MBeanServer mbs, Semaphore semaphore) { |
| this.mbs = mbs; |
| this.semaphore = semaphore; |
| } |
| |
| public ObjectName preRegister(MBeanServer mbs, ObjectName on) { |
| this.objectName = on; |
| return on; |
| } |
| |
| public void postRegister(Boolean done) {} |
| |
| public void preDeregister() throws Exception { |
| Thread t = new Thread() { |
| public void run() { |
| try { |
| mbs.unregisterMBean(objectName); |
| fail("Nested unregister succeeded"); |
| } catch (InstanceNotFoundException e) { |
| semaphore.release(); |
| } catch (Throwable e) { |
| e.printStackTrace(System.out); |
| fail(e.toString()); |
| } |
| } |
| }; |
| t.start(); |
| // Give the thread a chance to block so we are really |
| // testing parallelism. (On slow machines we might not |
| // really be testing it but we should be covered by our |
| // faster machines.) |
| Thread.sleep(500L); |
| } |
| |
| public void postDeregister() {} |
| |
| private final MBeanServer mbs; |
| private ObjectName objectName; |
| private final Semaphore semaphore; |
| } |
| |
| public static void main(String[] args) throws Exception { |
| MBeanServer mbs = MBeanServerFactory.newMBeanServer(); |
| ObjectName on1 = new ObjectName("a:type=Blibby,name=\"1\""); |
| ObjectName on2 = new ObjectName("a:type=Blibby,name=\"2\""); |
| |
| // Test 1: preDeregister starts a thread which unregisters a |
| // different MBean: this must not deadlock |
| mbs.registerMBean(new Blibby(mbs, on2), on1); |
| mbs.registerMBean(new Blibby(mbs, null), on2); |
| mbs.unregisterMBean(on1); |
| |
| // Test 2: preDeregister starts a thread which tries to |
| // unregister the same MBean: this thread should block until |
| // the original thread succeeds in unregistering, then |
| // get an InstanceNotFoundException. We wait for it to |
| // complete here, using the semaphore. |
| Semaphore semaphore = new Semaphore(0); |
| mbs.registerMBean(new Blobby(mbs, semaphore), on1); |
| mbs.unregisterMBean(on1); |
| boolean ok = semaphore.tryAcquire(1, 5, TimeUnit.SECONDS); |
| if (!ok) |
| fail("Second unregister thread did not complete"); |
| |
| if (failure == null) |
| System.out.println("OK: Test passed"); |
| else |
| throw new Exception("TEST FAILED: " + failure); |
| } |
| |
| private static void fail(String why) { |
| System.out.println("FAILED: " + why); |
| failure = why; |
| } |
| |
| private static volatile String failure; |
| } |