libjava/testsuite/libjava.lang/SyncTest.java

   1 // Test atomic increment via synchronized blocks.
   2 public class SyncTest implements Runnable {
   3   static int counter;
   4
   5   public void run() {
   6     // We cache the .class value; otherwise this code is
   7     // slow enough that it will time out in some situations.
   8     Object lock = SyncTest.class;
   9     for (int n = 0; n < 1000000; n++)
  10       synchronized (lock) {
  11         counter++;
  12       }
  13   }
  14
  15   public static void main(String[] args) {
  16     SyncTest test = new SyncTest();
  17     Thread[] thr = new Thread[4];
  18
  19     for (int n = 0; n < thr.length; n++) {
  20       thr[n] = new Thread(test);
  21       thr[n].start();
  22     }
  23
  24     for (int n = 0; n < thr.length; n++) {
  25       try {
  26         thr[n].join();
  27       } catch (InterruptedException ex) {
  28       }
  29     }
  30
  31     System.out.println(counter == 1000000 * thr.length ?
  32       "ok" : "fail: " + counter);
  33   }
  34 }