new Supplier<Boolean>() {
          boolean isWaiting(Thread thread) {
            switch (thread.getState()) {
              case BLOCKED:
              case WAITING:
              case TIMED_WAITING:
                return true;
              default:
                return false;
            }
          }

          int waitingThreads() {
            int waitingThreads = 0;

        new Supplier<Boolean>() {
          boolean isWaiting(Thread thread) {
            switch (thread.getState()) {
              case BLOCKED:
              case WAITING:
              case TIMED_WAITING:
                return true;
              default:
                return false;
            }
          }

          int waitingThreads() {
            int waitingThreads = 0;

      if (compareAndSet(currentRunner, blocker)) {
        // Thread.interrupt can throw arbitrary exceptions due to the nio InterruptibleChannel API
        // This will make sure that tasks don't get stuck busy waiting.
        // Some of this is fixed in jdk11 (see https://bugs.openjdk.java.net/browse/JDK-8198692) but
        // not all.  See the test cases for examples on how this can happen.
        try {

    @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
    Future<?> possiblyIgnoredError = threadPool.submit(new Interrupter(currentThread()));
    try {
      // if waiting works, this should get stuck
      Queues.drain(q, newArrayList(), 1, MAX_VALUE, NANOSECONDS);
      fail();
    } catch (InterruptedException expected) {

   * time.
   *
   * <p>Compare {@link #checkedPow}, which throws an {@link ArithmeticException} upon overflow.
   *
   * @throws IllegalArgumentException if {@code k < 0}
   */
  @GwtIncompatible // failing tests
  public static int pow(int b, int k) {
    checkNonNegative("exponent", k);
    switch (b) {
      case 0:
        return (k == 0) ? 1 : 0;
      case 1:
        return 1;
      case (-1):

   * 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;

    assertEquals("b", consumingIterator.next());
    assertThat(list).isEmpty();

    assertFalse(consumingIterator.hasNext());
  }

  @GwtIncompatible // ?
  // TODO: Figure out why this is failing in GWT.
  public void testConsumingIterable_duelingIterators() {
    // Test data
    List<String> list = Lists.newArrayList(asList("a", "b"));

    // Test & Verify

   *
   * @throws InterruptedException if interrupted while waiting
   */
  public void enterInterruptibly() throws InterruptedException {
    lock.lockInterruptibly();
  }

  /**
   * Enters this monitor. Blocks at most the given time, and may be interrupted.
   *
   * @return whether the monitor was entered
   * @throws InterruptedException if interrupted while waiting
   */

   * 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;

        assertTrue(aa.compareAndSet(i, prev, x));
        assertBitEquals(x, aa.get(i));
        prev = x;
      }
    }
  }

  /** compareAndSet in one thread enables another waiting for value to succeed */
  public void testCompareAndSetInMultipleThreads() throws InterruptedException {
    final AtomicDoubleArray a = new AtomicDoubleArray(1);
    a.set(0, 1.0);
    Thread t =