assertEquals(listener, jobExecutor.shutdownListener);

        // Verify listener is called on shutdown
        jobExecutor.shutdown();
        assertTrue(shutdownCalled.get());
    }

    public void test_addShutdownListener_replace() {
        // Test replacing shutdown listener
        AtomicInteger callCount = new AtomicInteger(0);
        ShutdownListener listener1 = new ShutdownListener() {

    /**
     * Initiates shutdown of the job executor.
     * This method notifies the shutdown listener to perform cleanup operations.
     */
    public void shutdown() {
        shutdownListener.onShutdown();
    }

    /**
     * Adds a shutdown listener to be notified when the executor is shutting down.
     *
     * @param listener the shutdown listener to add
     */

  /** Lock used whenever accessing the state variables (runningTasks, shutdown) of the executor */
  private final Object lock = new Object();

  /*
   * Conceptually, these two variables describe the executor being in
   * one of three states:
   *   - Active: shutdown == false
   *   - Shutdown: runningTasks > 0 and shutdown == true
   *   - Terminated: runningTasks == 0 and shutdown == true
   */
  @GuardedBy("lock")

    ExecutorService service = mock(ExecutorService.class);
    application.addDelayedShutdownHook(service, 2, SECONDS);
    verify(service, Mockito.never()).shutdown();
    application.shutdown();
    InOrder shutdownFirst = Mockito.inOrder(service);
    shutdownFirst.verify(service).shutdown();
    shutdownFirst.verify(service).awaitTermination(2, SECONDS);
  }

    private volatile boolean shutdown;

    @Override
    public void shutdown() {
      shutdown = true;
    }

    @Override
    public List<Runnable> shutdownNow() {
      shutdown();
      return ImmutableList.of();
    }

    @Override
    public boolean isShutdown() {
      return shutdown;
    }

    @Override
    public boolean isTerminated() {

  /** Lock used whenever accessing the state variables (runningTasks, shutdown) of the executor */
  private final Object lock = new Object();

  /*
   * Conceptually, these two variables describe the executor being in
   * one of three states:
   *   - Active: shutdown == false
   *   - Shutdown: runningTasks > 0 and shutdown == true
   *   - Terminated: runningTasks == 0 and shutdown == true
   */
  @GuardedBy("lock")

    }

    public void test_shutdown_withListener() {
        // Add shutdown listener
        TestShutdownListener listener = new TestShutdownListener();
        scriptExecutor.addShutdownListener(listener);

        // Verify listener not called yet
        assertFalse(listener.wasShutdownCalled());

        // Call shutdown
        scriptExecutor.shutdown();

        // Verify listener was called

    task: Task,
    delayNanos: Long = 0L,
  ) {
    taskRunner.withLock {
      if (shutdown) {
        if (task.cancelable) {
          taskRunner.logger.taskLog(task, this) { "schedule canceled (queue is shutdown)" }
          return
        }
        taskRunner.logger.taskLog(task, this) { "schedule failed (queue is shutdown)" }
        throw RejectedExecutionException()
      }

              while (!shutdown.get()) {
                interruptee.interrupt();
                Thread.yield();
              }
            }
          });
      this.shutdown = shutdown;
      start();
    }

    @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
    void shutdown() {
      shutdown.set(true);
      while (this.isAlive()) {
        Thread.yield();

    private volatile boolean shutdown;

    @Override
    public void shutdown() {
      shutdown = true;
    }

    @Override
    public List<Runnable> shutdownNow() {
      shutdown();
      return ImmutableList.of();
    }

    @Override
    public boolean isShutdown() {
      return shutdown;
    }

    @Override
    public boolean isTerminated() {