StringContentEqualsBug.java revision 12745:f068a4ffddd2 
1/*
2 * Copyright (c) 2013, 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 8014477
27 * @summary test String.contentEquals(StringBuffer)
28 */
29public class StringContentEqualsBug {
30
31    abstract static class Task extends Thread {
32        volatile StringBuffer sb;
33        volatile Exception exception;
34
35        Task(StringBuffer sb) {
36            this.sb = sb;
37        }
38
39        @Override
40        public void run() {
41            try {
42                StringBuffer sb;
43                while ((sb = this.sb) != null) {
44                    doWith(sb);
45                }
46            }
47            catch (Exception e) {
48                exception = e;
49            }
50        }
51
52        protected abstract void doWith(StringBuffer sb);
53    }
54
55    static class Tester extends Task {
56        Tester(StringBuffer sb) {
57            super(sb);
58        }
59
60        @Override
61        protected void doWith(StringBuffer sb) {
62            "AA".contentEquals(sb);
63        }
64    }
65
66    static class Disturber extends Task {
67        Disturber(StringBuffer sb) {
68            super(sb);
69        }
70
71        @Override
72        protected void doWith(StringBuffer sb) {
73            sb.setLength(0);
74            sb.trimToSize();
75            sb.append("AA");
76        }
77    }
78
79
80    public static void main(String[] args) throws Exception {
81        StringBuffer sb = new StringBuffer();
82        Task[] tasks = new Task[3];
83        (tasks[0] = new Tester(sb)).start();
84        for (int i = 1; i < tasks.length; i++) {
85            (tasks[i] = new Disturber(sb)).start();
86        }
87
88        try
89        {
90            // wait at most 5 seconds for any of the threads to throw exception
91            for (int i = 0; i < 20; i++) {
92                for (Task task : tasks) {
93                    if (task.exception != null) {
94                        throw task.exception;
95                    }
96                }
97                Thread.sleep(250L);
98            }
99        }
100        finally {
101            for (Task task : tasks) {
102                task.sb = null;
103                task.join();
104            }
105        }
106    }
107}
108