int waiters = guard.waiterCount++;
    if (waiters == 0) {
      // push guard onto activeGuards
      guard.next = activeGuards;
      activeGuards = guard;
    }
  }

  /** Records that the current thread is no longer waiting on the specified guard. */
  @GuardedBy("lock")
  private void endWaitingFor(Guard guard) {
    int waiters = --guard.waiterCount;

  volatile @Nullable Waiter waitersField;

  /** Non-volatile write of the thread to the {@link Waiter#thread} field. */
  private static void putThread(Waiter waiter, Thread newValue) {
    ATOMIC_HELPER.putThread(waiter, newValue);
  }

  /** Non-volatile write of the waiter to the {@link Waiter#next} field. */
  private static void putNext(Waiter waiter, @Nullable Waiter newValue) {

    // addListener says that listeners execute 'immediate' if the future isDone(). However, our
    // protocol for completing a future is to assign the value field (which sets isDone to true) and
    // then to release waiters, followed by executing afterDone(), followed by releasing listeners.
    // That means that it is possible to observe that the future isDone and that your listeners

    WaiterThread waiter1 = new WaiterThread(future);
    waiter1.start();
    waiter1.awaitWaiting();

    WaiterThread waiter2 = new WaiterThread(future);
    waiter2.start();
    waiter2.awaitWaiting();
    // The waiter queue should be waiter2->waiter1

    // This should wake up waiter1 and cause the waiter1 node to be removed.
    waiter1.interrupt();

    waiter1.join();

    WaiterThread waiter1 = new WaiterThread(future);
    waiter1.start();
    waiter1.awaitWaiting();

    WaiterThread waiter2 = new WaiterThread(future);
    waiter2.start();
    waiter2.awaitWaiting();
    // The waiter queue should be waiter2->waiter1

    // This should wake up waiter1 and cause the waiter1 node to be removed.
    waiter1.interrupt();

    waiter1.join();

        protected boolean isCommit = false;

        /** The temporary file to write changes to. */
        protected File newFile;

        /** The writer for the temporary file. */
        protected Writer writer;

        /** The stopword item being added or updated. */
        protected StopwordsItem item;

        /**
         * Constructs a new updater for a stopword item.
         *

        protected boolean isCommit = false;

        /** The temporary file to write changes to. */
        protected File newFile;

        /** The writer for the temporary file. */
        protected Writer writer;

        /** The stemmer override item being added or updated. */
        protected StemmerOverrideItem item;

        /**

        protected boolean isCommit = false;

        /** Temporary file for storing updates */
        protected File newFile;

        /** Writer for writing to the temporary file */
        protected Writer writer;

        /** The item being updated */
        protected ProtwordsItem item;

        /**
         * Constructor for ProtwordsUpdater.

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

    // 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);