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23 
24 /**
25  * @test
26  * @bug 8167108
27  * @summary Stress test java.lang.Thread.countStackFrames() at thread exit.
28  * @run main/othervm -Xlog:thread+smr=debug CountStackFramesAtExit
29  */
30 
31 import java.util.concurrent.CountDownLatch;
32 
33 public class CountStackFramesAtExit extends Thread {
34     final static int N_THREADS = 32;
35     final static int N_LATE_CALLS = 1000;
36 
37     public CountDownLatch exitSyncObj = new CountDownLatch(1);
38     public CountDownLatch startSyncObj = new CountDownLatch(1);
39 
40     @Override
run()41     public void run() {
42         // Tell main thread we have started.
43         startSyncObj.countDown();
44         try {
45             // Wait for main thread to interrupt us so we
46             // can race to exit.
47             exitSyncObj.await();
48         } catch (InterruptedException e) {
49             // ignore because we expect one
50         }
51     }
52 
main(String[] args)53     public static void main(String[] args) {
54         CountStackFramesAtExit threads[] = new CountStackFramesAtExit[N_THREADS];
55 
56         for (int i = 0; i < N_THREADS; i++ ) {
57             threads[i] = new CountStackFramesAtExit();
58             int late_count = 1;
59             threads[i].start();
60             try {
61                 // Wait for the worker thread to get going.
62                 threads[i].startSyncObj.await();
63 
64                 // This interrupt() call will break the worker out of
65                 // the exitSyncObj.await() call and the countStackFrames()
66                 // calls will come in during thread exit.
67                 threads[i].interrupt();
68                 for (; late_count <= N_LATE_CALLS; late_count++) {
69                     try {
70                         threads[i].countStackFrames();
71                     } catch (IllegalThreadStateException itse) {
72                         // ignore because we expect it
73                     }
74 
75                     if (!threads[i].isAlive()) {
76                         // Done with Thread.countStackFrames() calls since
77                         // thread is not alive.
78                         break;
79                     }
80                 }
81             } catch (InterruptedException e) {
82                 throw new Error("Unexpected: " + e);
83             }
84 
85             System.out.println("INFO: thread #" + i + ": made " + late_count +
86                                " late calls to java.lang.Thread.countStackFrames()");
87             System.out.println("INFO: thread #" + i + ": N_LATE_CALLS==" +
88                                N_LATE_CALLS + " value is " +
89                                ((late_count >= N_LATE_CALLS) ? "NOT " : "") +
90                                "large enough to cause a Thread.countStackFrames() " +
91                                "call after thread exit.");
92 
93             try {
94                 threads[i].join();
95             } catch (InterruptedException e) {
96                 throw new Error("Unexpected: " + e);
97             }
98             threads[i].countStackFrames();
99             if (threads[i].isAlive()) {
100                 throw new Error("Expected !Thread.isAlive() after thread #" +
101                                 i + " has been join()'ed");
102             }
103         }
104 
105         String cmd = System.getProperty("sun.java.command");
106         if (cmd != null && !cmd.startsWith("com.sun.javatest.regtest.agent.MainWrapper")) {
107             // Exit with success in a non-JavaTest environment:
108             System.exit(0);
109         }
110     }
111 }
112