// Test with listener1
        factory.setOnDestroyListener(listener1);
        assertEquals(listener1, factory.getOnDestroyListener());
        factory.destroyObject(pooledObject);
        assertEquals(1, events.size());
        assertEquals("listener1", events.get(0));

        // Switch to listener2
        factory.setOnDestroyListener(listener2);
        assertEquals(listener2, factory.getOnDestroyListener());

        // Add second listener (should replace first)
        TestShutdownListener listener2 = new TestShutdownListener();
        scriptExecutor.addShutdownListener(listener2);

        // Call shutdown
        scriptExecutor.shutdown();

        // Verify only second listener was called
        assertFalse(listener1.wasShutdownCalled());
        assertTrue(listener2.wasShutdownCalled());

   * across calls to multiple listeners. Specifically, a given listener will have its callbacks
   * invoked in the same order as the underlying service enters those states. Additionally, at most
   * one of the listener's callbacks will execute at once. However, multiple listeners' callbacks
   * may execute concurrently, and listeners may execute in an order different from the one in which
   * they were registered.

    void enqueueStoppedEvent() {
      listeners.enqueue(STOPPED_EVENT);
    }

    void enqueueHealthyEvent() {
      listeners.enqueue(HEALTHY_EVENT);
    }

    void enqueueFailedEvent(Service service) {
      listeners.enqueue(
          new ListenerCallQueue.Event<Listener>() {
            @Override
            public void call(Listener listener) {
              listener.failure(service);
            }

   * across calls to multiple listeners. Specifically, a given listener will have its callbacks
   * invoked in the same order as the underlying service enters those states. Additionally, at most
   * one of the listener's callbacks will execute at once. However, multiple listeners' callbacks
   * may execute concurrently, and listeners may execute in an order different from the one in which
   * they were registered.

    }

    /**
     * Add a listener for circuit breaker events
     *
     * @param listener the listener to add
     */
    public void addListener(CircuitBreakerListener listener) {
        if (listener != null) {
            listeners.add(listener);
        }
    }

    /**
     * Remove a listener
     *
     * @param listener the listener to remove
     */

   * @since 13.0
   */
  @Override
  public final void addListener(Listener listener, Executor executor) {
    listeners.addListener(listener, executor);
  }

  @Override
  public String toString() {
    return getClass().getSimpleName() + " [" + state() + "]";
  }

  /**
   * Attempts to execute all the listeners in {@link #listeners} while not holding the {@link
   * #monitor}.
   */

   * @since 13.0
   */
  @Override
  public final void addListener(Listener listener, Executor executor) {
    listeners.addListener(listener, executor);
  }

  @Override
  public String toString() {
    return getClass().getSimpleName() + " [" + state() + "]";
  }

  /**
   * Attempts to execute all the listeners in {@link #listeners} while not holding the {@link
   * #monitor}.
   */

        return updateScope;
    }

    private void fireEvent(int event, List<ResolutionListener> listeners, ResolutionNode node) {
        fireEvent(event, listeners, node, null);
    }

    private void fireEvent(int event, List<ResolutionListener> listeners, ResolutionNode node, Artifact replacement) {
        fireEvent(event, listeners, node, replacement, null);
    }

    private void fireEvent(
            int event,

                WitnessNotificationListener listener = listeners.get(entry.getKey());
                if (listener != null) {
                    try {
                        listener.onWitnessNotification(notification);
                    } catch (Exception e) {
                        log.error("Error in witness notification listener", e);
                    }
                }
            }