Thread t = this.thread;
        if ( t != null && Thread.currentThread() != t ) {
            this.thread = null;
            try {
                log.debug("Interrupting transport thread");
                t.interrupt();
                log.debug("Joining transport thread");
                t.join(timeout);

    Stopwatch stopwatch = Stopwatch.createStarted();
    Thread thread = new Thread(new JoinTarget(15));
    thread.start();
    thread.join();
    assertFalse(thread.isAlive());

    joinUninterruptibly(thread);
    joinUninterruptibly(thread, 0, MILLISECONDS);
    joinUninterruptibly(thread, -42, MILLISECONDS);
    joinUninterruptibly(thread, LONG_DELAY_MS, MILLISECONDS);

        directExecutor());
    service.startAsync().awaitRunning();

    Thread thread =
        new Thread() {
          @Override
          public void run() {
            service.stopAsync().awaitTerminated();
          }
        };
    thread.start();
    thread.join(LONG_TIMEOUT_MILLIS);
    assertFalse(thread + " is deadlocked", thread.isAlive());
  }

        }
      }
    } finally {
      if (interrupted) {
        Thread.currentThread().interrupt();
      }
    }
  }

  /** Invokes {@code toJoin.}{@link Thread#join() join()} uninterruptibly. */
  @J2ktIncompatible
  @GwtIncompatible // concurrency
  public static void joinUninterruptibly(Thread toJoin) {
    boolean interrupted = false;
    try {
      while (true) {
        try {

    @Override
    public boolean equals(@Nullable Object object) {
      assertTrue(Thread.holdsLock(mutex));
      return super.equals(object);
    }

    @Override
    public K getKey() {
      assertTrue(Thread.holdsLock(mutex));
      return super.getKey();
    }

    @Override
    public V getValue() {
      assertTrue(Thread.holdsLock(mutex));
      return super.getValue();
    }

    @Override

  @GuardedBy("queue")
  private WorkerRunningState workerRunningState = IDLE;

  /**
   * This counter prevents an ABA issue where a thread may successfully schedule the worker, the
   * worker runs and exhausts the queue, another thread enqueues a task and fails to schedule the
   * worker, and then the first thread's call to delegate.execute() returns. Without this counter,

        block_fetcher_(block_fetcher),
        timer_seconds_(timer_seconds),
        pruning_thread_(nullptr,
                        [](TF_Thread* thread) { TF_JoinThread(thread); }) {
    if (max_staleness_ > 0) {
      TF_ThreadOptions thread_options;
      TF_DefaultThreadOptions(&thread_options);
      pruning_thread_.reset(
          TF_StartThread(&thread_options, "TF_prune_FBC", PruneThread, this));
    }

     *       observing a null thread does not mean the object is safe to reuse.
     *   <li>If this field's value is some other thread object, we know that it's not our thread.
     *   <li>If this field's value == null because it originally belonged to another thread and that
     *       thread cleared it, we still know that it's not associated with our thread

        directExecutor());
    service.startAsync().awaitRunning();

    Thread thread =
        new Thread() {
          @Override
          public void run() {
            service.stopAsync().awaitTerminated();
          }
        };
    thread.start();
    thread.join(LONG_TIMEOUT_MILLIS);
    assertFalse(thread + " is deadlocked", thread.isAlive());
  }

    Stopwatch stopwatch = Stopwatch.createStarted();
    Thread thread = new Thread(new JoinTarget(15));
    thread.start();
    thread.join();
    assertFalse(thread.isAlive());

    joinUninterruptibly(thread);
    joinUninterruptibly(thread, 0, MILLISECONDS);
    joinUninterruptibly(thread, -42, MILLISECONDS);
    joinUninterruptibly(thread, LONG_DELAY_MS, MILLISECONDS);