// Methods only in Iterables, not in Iterators

  /**
   * Determines if the given iterable contains no elements.
   *
   * <p>There is no precise {@link Iterator} equivalent to this method, since one can only ask an
   * iterator whether it has any elements <i>remaining</i> (which one does using {@link
   * Iterator#hasNext}).
   *
   * <p><b>{@code Stream} equivalent:</b> {@code !stream.findAny().isPresent()}
   *

      if ((radix & (radix - 1)) == 0) {
        // Radix is a power of two so we can avoid division.
        int shift = Integer.numberOfTrailingZeros(radix);
        int mask = radix - 1;
        do {
          buf[--i] = Character.forDigit(((int) x) & mask, radix);
          x >>>= shift;
        } while (x != 0);
      } else {
        // Separate off the last digit using unsigned division. That will leave

              }
            });
    Runnable task =
        new Runnable() {
          @Override
          public void run() {
            numCalls.incrementAndGet();
          }
        };
    assertThrows(RejectedExecutionException.class, () -> executor.execute(task));
    assertEquals(0, numCalls.get());
    reject.set(false);
    executor.execute(task);
    assertEquals(1, numCalls.get());
  }

  }

  @Override
  public final Future<?> submit(Runnable task) {
    return delegate.submit(wrapTask(task));
  }

  @Override
  public final <T extends @Nullable Object> Future<T> submit(
      Runnable task, @ParametricNullness T result) {
    return delegate.submit(wrapTask(task), result);
  }

  @Override
  public final <T extends @Nullable Object> List<Future<T>> invokeAll(

  @Override
  public ListenableFuture<?> submit(Runnable task) {
    return (ListenableFuture<?>) super.submit(task);
  }

  @CanIgnoreReturnValue // TODO(kak): consider removing this
  @Override
  public <T extends @Nullable Object> ListenableFuture<T> submit(
      Runnable task, @ParametricNullness T result) {
    return (ListenableFuture<T>) super.submit(task, result);
  }

  private static class QueuingExecutor implements Executor {
    private final Deque<Runnable> tasks = Queues.newArrayDeque();

    @Override
    public void execute(Runnable task) {
      tasks.add(task);
    }

    private void runNext() {
      tasks.removeFirst().run();
    }
  }

  public void testAsyncReload() throws Exception {
    final AtomicInteger loadCount = new AtomicInteger();

    allTasks.add(setFutureCompleteExceptionallyRunnable);
    allTasks.add(setFutureCancelRunnable);
    for (int k = 0; k < 50; k++) {
      // For each listener we add a task that submits it to the executor directly for the blocking
      // get use case and another task that adds it as a listener to the future to exercise both
      // racing addListener calls and addListener calls completing after the future completes.
      final Runnable listener =

    @CheckForNull // null only for TOMBSTONE
    final Runnable task;
    @CheckForNull // null only for TOMBSTONE
    final Executor executor;

    // writes to next are made visible by subsequent CAS's on the listeners field
    @CheckForNull Listener next;

    Listener(Runnable task, Executor executor) {
      this.task = task;
      this.executor = executor;
    }

    Listener() {

          }
        });
  }

  private long doMultithreadedLoop(Callable<Long> task)
      throws InterruptedException, ExecutionException {

    List<Future<Long>> futures = Lists.newArrayListWithCapacity(threads);
    for (int i = 0; i < threads; i++) {
      futures.add(threadPool.submit(task));
    }
    long total = 0;
    for (Future<Long> future : futures) {
      total += future.get();
    }

   * wait for 100 seconds, and /then/ start the actual task. Why wait without doing anything? A much
   * better approach is to /allow/ the request right away (as if it was an acquire(1) request
   * instead), and postpone /subsequent/ requests as needed. In this version, we allow starting the
   * task immediately, and postpone by 100 seconds future requests, thus we allow for work to get