// Check that we wait long enough anyway (presumably as long as MAX_VALUE nanos):
    TimedWaiterThread waiter = new TimedWaiterThread(future, Long.MAX_VALUE, SECONDS);
    waiter.start();
    waiter.awaitWaiting();

    future.set(1);
    waiter.join();
  }

  @J2ktIncompatible // TODO(b/324550390): Enable
  public void testSetNull() throws Exception {
    future.set(null);

    waiter2.join();
  }

  public void testRemoveWaiter_polling() throws Exception {
    final AbstractFuture<String> future = new AbstractFuture<String>() {};
    WaiterThread waiter = new WaiterThread(future);
    waiter.start();
    waiter.awaitWaiting();
    PollingThread poller = new PollingThread(future);
    poller.start();
    PollingThread poller2 = new PollingThread(future);
    poller2.start();

      entries[srcIndex] = 0;

      // also need to update whoever's "next" pointer was pointing to the last entry place
      int tableIndex = smearedHash(object) & mask;
      int next = CompactHashing.tableGet(table, tableIndex);
      int srcNext = srcIndex + 1;
      if (next == srcNext) {
        // we need to update the root pointer
        CompactHashing.tableSet(table, tableIndex, dstIndex + 1);
      } else {

  private ExecutionSequencer() {}

  /** Creates a new instance. */
  public static ExecutionSequencer create() {
    return new ExecutionSequencer();
  }

  /** This reference acts as a pointer tracking the head of a linked list of ListenableFutures. */
  private final AtomicReference<ListenableFuture<@Nullable Void>> ref =
      new AtomicReference<>(immediateVoidFuture());

   *
   * <p>Currently, the UNSET value means "null pointer", and any non negative value x is the actual
   * index.
   *
   * <p>Its size must be a power of two.
   */
  private transient int[] table;

  /**
   * Contains the logical entries, in the range of [0, size()). The high 32 bits of each long is the
   * smeared hash of the element, whereas the low 32 bits is the "next" pointer (pointing to the

    Thread waiter =
        new Thread() {
          @Override
          public void run() {
            try {
              service.awaitTermination(1, TimeUnit.DAYS);
            } catch (InterruptedException e) {
              return;
            }
          }
        };
    waiter.start();
    awaitTimedWaiting(waiter);
    service.shutdown();

      entries[srcIndex] = 0;

      // also need to update whoever's "next" pointer was pointing to the last entry place
      int tableIndex = smearedHash(key) & mask;
      int next = CompactHashing.tableGet(table, tableIndex);
      int srcNext = srcIndex + 1;
      if (next == srcNext) {
        // we need to update the root pointer
        CompactHashing.tableSet(table, tableIndex, dstIndex + 1);
      } else {

    waiter2.join();
  }

  public void testRemoveWaiter_polling() throws Exception {
    final AbstractFuture<String> future = new AbstractFuture<String>() {};
    WaiterThread waiter = new WaiterThread(future);
    waiter.start();
    waiter.awaitWaiting();
    PollingThread poller = new PollingThread(future);
    poller.start();
    PollingThread poller2 = new PollingThread(future);
    poller2.start();

   * Normally used as a C string terminator.
   *
   * <p>Although RFC 20 names this as "Null", note that it is distinct from the C/C++ "NULL"
   * pointer.
   *
   * @since 8.0
   */
  public static final byte NUL = 0;

  /**
   * Start of Heading: A communication control character used at the beginning of a sequence of

   */
  protected final <T> void setDefault(Class<T> type, T value) {
    tester.setDefault(type, value);
  }

  /**
   * Sets two distinct values for {@code type}. These values can be used for both null pointer
   * testing and equals testing.
   *
   * @since 17.0
   */
  protected final <T> void setDistinctValues(Class<T> type, T value1, T value2) {
    tester.setDistinctValues(type, value1, value2);
  }