* example involving two locks and two threads, deadlock occurs when one thread acquires Lock A, and
 * then Lock B, while another thread acquires Lock B, and then Lock A:
 *
 * <pre>
 * Thread1: acquire(LockA) --X acquire(LockB)
 * Thread2: acquire(LockB) --X acquire(LockA)
 * </pre>
 *
 * <p>Neither thread will progress because each is waiting for the other. In more complex

    for (int i = 0; i < numThreads; i++) {
      threads[i] =
          new Thread() {
            @Override
            public void run() {
              assertSame(Boolean.TRUE, memoizedSupplier.get());
            }
          };
    }
    for (Thread t : threads) {
      t.start();
    }
    for (Thread t : threads) {
      t.join();
    }

    if (thrown.get() != null) {

    for (int i = 0; i < numThreads; i++) {
      threads[i] =
          new Thread() {
            @Override
            public void run() {
              assertSame(Boolean.TRUE, memoizedSupplier.get());
            }
          };
    }
    for (Thread t : threads) {
      t.start();
    }
    for (Thread t : threads) {
      t.join();
    }

    if (thrown.get() != null) {

    start();
  }

  // Thread.stop() is okay because all threads started by a test are dying at the end of the test,
  // so there is no object state put at risk by stopping the threads abruptly. In some cases a test
  // may put a thread into an uninterruptible operation intentionally, so there is no other way to
  // clean up these threads.
  @SuppressWarnings("deprecation")
  @Override

   * state: BLOCKED, WAITING, or TIMED_WAITING.
   */
  void waitForThreadToEnterWaitState(Thread thread, long timeoutMillis) {
    long startTime = System.nanoTime();
    for (; ; ) {
      Thread.State s = thread.getState();
      if (s == Thread.State.BLOCKED || s == Thread.State.WAITING || s == Thread.State.TIMED_WAITING)
        return;

   *       directExecutor}, the listener can execute in any of three possible threads:
   *       <ol>
   *         <li>When a thread attaches a listener to a {@code ListenableFuture} that's already
   *             complete, the listener runs immediately in that thread.
   *         <li>When a thread attaches a listener to a {@code ListenableFuture} that's

   * state: BLOCKED, WAITING, or TIMED_WAITING.
   */
  void waitForThreadToEnterWaitState(Thread thread, long timeoutMillis) {
    long startTime = System.nanoTime();
    for (; ; ) {
      Thread.State s = thread.getState();
      if (s == Thread.State.BLOCKED || s == Thread.State.WAITING || s == Thread.State.TIMED_WAITING)
        return;

    start();
  }

  // Thread.stop() is okay because all threads started by a test are dying at the end of the test,
  // so there is no object state put at risk by stopping the threads abruptly. In some cases a test
  // may put a thread into an uninterruptible operation intentionally, so there is no other way to
  // clean up these threads.
  @SuppressWarnings("deprecation")
  @Override

   *
   * <p>On the other hand, if a signalled thread wakes up to discover that its guard is still not
   * satisfied, it does *not* need to call this method before returning to wait. This can only
   * happen due to spurious wakeup (ignorable) or another thread acquiring the lock before the
   * current thread can and returning the guard to the unsatisfied state. In the latter case the

      throw AssertionError("Thread ${Thread.currentThread().name} MUST hold lock on $this")
    }
  }

  @Suppress("NOTHING_TO_INLINE")
  internal inline fun Any.assertThreadDoesntHoldLock() {
    if (assertionsEnabled && taskRunner.lock.isHeldByCurrentThread) {
      throw AssertionError("Thread ${Thread.currentThread().name} MUST NOT hold lock on $this")
    }
  }