1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
/*
* 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 6331746
* @summary Test a deadlock and will be blocked forever if the deadlock is present.
* @author Shanliang JIANG
*
* @run main DeadlockTest
*/
import javax.management.*;
import javax.management.timer.*;
public class DeadlockTest extends StandardMBean {
public <T> DeadlockTest(T implementation, Class<T> mbeanInterface)
throws NotCompliantMBeanException {
super(implementation, mbeanInterface);
}
public MBeanInfo getCachedMBeanInfo() {
return super.getCachedMBeanInfo();
}
public void cacheMBeanInfo(MBeanInfo mi) {
super.cacheMBeanInfo(mi);
}
public static void main(String[] args) throws Exception {
System.out.println("main: No deadlock please.");
System.out.println("main: Create a BadBay to hold the lock forever.");
DeadlockTest dt = new DeadlockTest(new Timer(), TimerMBean.class);
BadBoy bb = new BadBoy(dt);
bb.start();
synchronized(bb) {
while(!bb.gotLock) {
bb.wait(); // if blocked here, means failing to get lock, impossible.
}
}
System.out.println("main: The BadBay is holding the lock forever.");
System.out.println("main: Create a WorkingBoy to see blocking ...");
WorkingBoy wb = new WorkingBoy(dt);
synchronized(wb) {
wb.start();
while(!wb.done) {
wb.wait(); // if blocked here, the deadlock happends
}
}
System.out.println("main: OK, bye bye.");
}
private static class BadBoy extends Thread {
public BadBoy(Object o) {
setDaemon(true);
this.o = o;
}
public void run() {
System.out.println("BadBoy-run: keep synchronization lock forever!");
synchronized(o) {
synchronized(this) {
gotLock = true;
this.notify();
}
try {
Thread.sleep(10000000);
} catch (Exception e) {
// OK
}
}
}
final Object o;
public boolean gotLock;
}
private static class WorkingBoy extends Thread {
public WorkingBoy(DeadlockTest sm) {
setDaemon(true);
this.sm = sm;
}
public void run() {
try {
System.out.println("WorkingBoy-run: calling StandardMBean methods ...");
System.out.println("WorkingBoy-run: calling setImplementation ...");
sm.setImplementation(new Timer());
System.out.println("WorkingBoy-run: calling getImplementation ...");
sm.getImplementation();
System.out.println("WorkingBoy-run: calling getMBeanInterface ...");
sm.getMBeanInterface();
System.out.println("WorkingBoy-run: calling getImplementationClass ...");
sm.getImplementationClass();
System.out.println("WorkingBoy-run: calling cacheMBeanInfo ...");
sm.cacheMBeanInfo(null);
System.out.println("WorkingBoy-run: calling getCachedMBeanInfo ...");
sm.getCachedMBeanInfo();
System.out.println("WorkingBoy-run: All done!");
synchronized(this) {
done = true;
this.notifyAll();
}
} catch (NotCompliantMBeanException ne) {
// Impossible?
throw new RuntimeException(ne);
}
}
final DeadlockTest sm;
public boolean done;
}
}
|
