for (int i = 0; i < SIZE; i++) {
      aa.set(i, (double) COUNTDOWN);
    }
    Counter c1 = new Counter(aa);
    Counter c2 = new Counter(aa);
    Thread t1 = newStartedThread(c1);
    Thread t2 = newStartedThread(c2);
    awaitTermination(t1);
    awaitTermination(t2);
    assertEquals(SIZE * COUNTDOWN, c1.counts + c2.counts);
  }

  /** a deserialized serialized array holds same values */

  public void testCompareAndSetInMultipleThreads() throws Exception {
    final AtomicDouble at = new AtomicDouble(1.0);
    Thread t =
        newStartedThread(
            new CheckedRunnable() {
              @Override
              @SuppressWarnings("ThreadPriorityCheck") // doing our best to test for races
              public void realRun() {

   */
  long millisElapsedSince(long startNanoTime) {
    return NANOSECONDS.toMillis(System.nanoTime() - startNanoTime);
  }

  /** Returns a new started daemon Thread running the given runnable. */
  Thread newStartedThread(Runnable runnable) {
    Thread t = new Thread(runnable);
    t.setDaemon(true);
    t.start();
    return t;
  }

  /**

   */
  long millisElapsedSince(long startNanoTime) {
    return NANOSECONDS.toMillis(System.nanoTime() - startNanoTime);
  }

  /** Returns a new started daemon Thread running the given runnable. */
  Thread newStartedThread(Runnable runnable) {
    Thread t = new Thread(runnable);
    t.setDaemon(true);
    t.start();
    return t;
  }

  /**