1 /*
2 * Copyright (c) 2005, 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 /*
26 * @test
27 * @bug 5086470
28 * @key intermittent
29 * @summary Basic Test for the following methods:
30 * - ThreadMXBean.findDeadlockedThreads()
31 * - ThreadMXBean.findMonitorDeadlockedThreads()
32 * @author Mandy Chung
33 *
34 * @modules java.management
35 * @build MonitorDeadlock
36 * @build SynchronizerDeadlock
37 * @build ThreadDump
38 * @run main/othervm FindDeadlocks
39 */
40
41 import java.lang.management.*;
42 import java.util.*;
43
44 public class FindDeadlocks {
45 static ThreadMXBean mbean = ManagementFactory.getThreadMXBean();
46 public static void main(String[] argv) {
47 ThreadMXBean mbean = ManagementFactory.getThreadMXBean();
48 // create deadlocked threads
49 MonitorDeadlock md = new MonitorDeadlock();
50
51 // no deadlock
52 if (findDeadlocks() != null) {
53 throw new RuntimeException("TEST FAILED: Should return null.");
54 }
55
56 // Let the threads to proceed
57 md.goDeadlock();
58 // wait until the deadlock is ready
59 md.waitUntilDeadlock();
60
61 long[] mthreads = findDeadlocks();
62 if (mthreads == null) {
63 ThreadDump.dumpStacks();
64 throw new RuntimeException("TEST FAILED: Deadlock not detected.");
65 }
66 md.checkResult(mthreads);
67
68 // create deadlocked threads on synchronizers
69 SynchronizerDeadlock sd = new SynchronizerDeadlock();
70
71 // Let the threads to proceed
72 sd.goDeadlock();
73 // wait until the deadlock is ready
74 sd.waitUntilDeadlock();
75
76 // Find Deadlock
77 long[] threads = findDeadlocks();
78 if (threads == null) {
79 ThreadDump.dumpStacks();
80 throw new RuntimeException("TEST FAILED: Deadlock not detected.");
81 }
82
83 // form a list of newly deadlocked threads
84 long[] newList = new long[threads.length - mthreads.length];
85 int count = 0;
86 for (int i = 0; i < threads.length; i++) {
87 long id = threads[i];
88 boolean isNew = true;
89 for (int j = 0; j < mthreads.length; j++) {
90 if (mthreads[j] == id) {
91 isNew = false;
92 break;
93 }
94 }
95 if (isNew) {
96 newList[count++] = id;
97 }
98 }
99
100 if (mbean.isSynchronizerUsageSupported()) {
101 sd.checkResult(newList);
102 } else {
103 // monitoring of synchronizer usage not supported
104 if (count != 0) {
105 throw new RuntimeException("TEST FAILED: NewList should be empty.");
106 }
107 }
108
109 // Print Deadlock stack trace
110 System.out.println("Found threads that are in deadlock:-");
111 ThreadInfo[] infos = mbean.getThreadInfo(threads, Integer.MAX_VALUE);
112 for (int i = 0; i < infos.length; i++) {
113 ThreadDump.printThreadInfo(infos[i]);
114 }
115
116 System.out.println("Test passed");
117 }
118 static long[] findDeadlocks() {
119 long[] threads;
120 if (mbean.isSynchronizerUsageSupported()) {
121 threads = mbean.findDeadlockedThreads();
122 } else {
123 threads = mbean.findMonitorDeadlockedThreads();
124 }
125 return threads;
126 }
127
128 }