assertEquals(listener, jobExecutor.shutdownListener);

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

    @Test
    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")

        return
      }
    }
    throw AssertionError("No such job: $url")
  }

  override fun shutdown() {
    shutdown = true
  }

  override fun shutdownNow(): List<Runnable> = throw UnsupportedOperationException()

  override fun isShutdown(): Boolean = shutdown

  override fun isTerminated(): Boolean = throw UnsupportedOperationException()

  override fun awaitTermination(

		return srv.Serve(l)
	}

	return serve, err
}

// Shutdown - shuts down HTTP server.
func (srv *Server) Shutdown() error {
	srv.listenerMutex.Lock()
	if srv.listener == nil {
		srv.listenerMutex.Unlock()
		return http.ErrServerClosed
	}
	srv.listenerMutex.Unlock()

	if atomic.AddUint32(&srv.inShutdown, 1) > 1 {
		// shutdown in progress
		return http.ErrServerClosed
	}

    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() {

    return delegate().invokeAny(tasks, timeout, unit);
  }

  @Override
  public boolean isShutdown() {
    return delegate().isShutdown();
  }

  @Override
  public boolean isTerminated() {
    return delegate().isTerminated();
  }

  @Override
  public void shutdown() {
    delegate().shutdown();
  }

  @Override
  @CanIgnoreReturnValue
  public List<Runnable> shutdownNow() {

  // The remaining methods just delegate.

  @Override
  public final void shutdown() {
    delegate.shutdown();
  }

  @Override
  @CanIgnoreReturnValue
  public final List<Runnable> shutdownNow() {
    return delegate.shutdownNow();
  }

  @Override
  public final boolean isShutdown() {
    return delegate.isShutdown();
  }

  @Override
  public final boolean isTerminated() {

    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() {

  private final ListeningExecutorService delegate = newDirectExecutorService();

  @Override
  public void shutdown() {
    delegate.shutdown();
  }

  @Override
  public List<Runnable> shutdownNow() {
    return delegate.shutdownNow();
  }

  @Override
  public boolean isShutdown() {
    return delegate.isShutdown();
  }

  @Override
  public boolean isTerminated() {
    return delegate.isTerminated();
  }