1 /*
2 * Copyright (c) 2006, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /*
25 * @test
26 * @bug 6417044
27 * @summary Test deadlock in MBeanRegistration.postRegister method
28 * @author Eamonn McManus, Daniel Fuchs
29 * @modules java.management
30 * @run clean PostRegisterDeadlockTest
31 * @run build PostRegisterDeadlockTest
32 * @run main PostRegisterDeadlockTest
33 */
34
35 import java.lang.Thread.State;
36 import java.util.concurrent.*;
37 import javax.management.*;
38
39 public class PostRegisterDeadlockTest {
40 public static interface BlibbyMBean {}
41
42 public static class Blibby implements BlibbyMBean, MBeanRegistration {
43 public Blibby(MBeanServer mbs, ObjectName otherName) {
44 this.mbs = mbs;
45 this.otherName = otherName;
46 }
47
48 public ObjectName preRegister(MBeanServer mbs, ObjectName on) {
49 return on;
50 }
51
52 public void preDeregister() {}
53
54 public void postRegister(Boolean done) {
55 // If no other MBean was registered
56 // do nothing.
57 //
58 if (otherName == null) return;
59
60 // Check that we can unregister
61 // other MBean
62 try {
63 Thread t = new Thread() {
64 public void run() {
65 try {
66 try {
67 mbs.unregisterMBean(otherName);
68 } catch (InstanceNotFoundException x) {
69 // Race condition!
70 System.out.println(otherName+
71 " was unregistered by main thread.");
72 }
73 } catch (Throwable e) {
74 e.printStackTrace(System.out);
75 fail(e.toString());
76 }
77 }
78 };
79 t.start();
80 t.join(5000L);
81 if (t.isAlive()) {
82 if (t.getState().equals(State.BLOCKED))
83 fail("Deadlock detected");
84 else
85 fail("Test not conclusive: "+
86 "Thread is alive but not blocked.");
87 }
88 } catch (Throwable e) {
89 e.printStackTrace(System.out);
90 fail(e.toString());
91 }
92 }
93
94 public void postDeregister() {}
95
96 private final MBeanServer mbs;
97 private final ObjectName otherName;
98 }
99
100 public static void main(String[] args) throws Exception {
101 String previous = null;
102 MBeanServer mbs = MBeanServerFactory.newMBeanServer();
103 ObjectName on1 = new ObjectName("a:type=Blibby,name=\"1\"");
104 ObjectName on2 = new ObjectName("a:type=Blibby,name=\"2\"");
105
106
107 // Test 1:
108 // 1 MBean is registered with on1
109 // Another MBean is registered with on1, postRegister(FALSE) is
110 // called, and the second MBean attempts to unregister first MBean in
111 // postRegister:
112 // postRegister starts a thread which unregisters the first MBean:
113 // this must not deadlock
114 //
115 System.out.println("\n**** TEST #1 ****\n");
116 System.out.println("Registering Blibby #1 with name: " + on1);
117 mbs.registerMBean(new Blibby(mbs, null), on1);
118 try {
119 System.out.println("Registering Blibby #2 with same name: " + on1);
120 mbs.registerMBean(new Blibby(mbs, on1), on1);
121 } catch (InstanceAlreadyExistsException x) {
122 System.out.println("Received expected exception: " + x);
123 }
124 if (mbs.isRegistered(on1)) {
125 try {
126 mbs.unregisterMBean(on1);
127 if (failure == null)
128 fail(on1+" should have been unregistered");
129 } catch (InstanceNotFoundException x) {
130 // Race condition!
131 System.out.println(on1+" was unregistered by mbean thread.");
132 }
133 } else {
134 System.out.println(on1+" was correctly unregistered.");
135 }
136
137 if (failure == previous)
138 System.out.println("\n**** TEST #1 PASSED ****\n");
139
140 previous = failure;
141
142 // Test 2:
143 // 1 MBean is registered with on1
144 // Another MBean is registered with on2, postRegister(TRUE) is
145 // called, and the second MBean attempts to unregister first MBean in
146 // postRegister:
147 // postRegister starts a thread which unregisters the first MBean:
148 // this must not deadlock
149 //
150 System.out.println("\n**** TEST #2 ****\n");
151 System.out.println("Registering Blibby #1 with name: " + on1);
152 mbs.registerMBean(new Blibby(mbs, null), on1);
153 System.out.println("Registering Blibby #2 with other name: " + on2);
154 mbs.registerMBean(new Blibby(mbs, on1), on2);
155 if (mbs.isRegistered(on1)) {
156 try {
157 mbs.unregisterMBean(on1);
158 if (failure == null)
159 fail(on1+" should have been unregistered");
160 } catch (InstanceNotFoundException x) {
161 // Race condition!
162 System.out.println(on1+" was unregistered by mbean thread.");
163 }
164 } else {
165 System.out.println(on1+" was correctly unregistered.");
166 }
167
168 System.out.println("unregistering "+on2);
169 mbs.unregisterMBean(on2);
170 if (failure == previous)
171 System.out.println("\n**** TEST #2 PASSED ****\n");
172 previous = failure;
173
174 if (failure == null)
175 System.out.println("OK: Test passed");
176 else
177 throw new Exception("TEST FAILED: " + failure);
178 }
179
180 private static void fail(String why) {
181 System.out.println("FAILED: " + why);
182 failure = (failure == null)?why:(failure+",\n"+why);
183 }
184
185 private static volatile String failure;
186 }