try {
      insert(e);
    } finally {
      monitor.leave();
    }
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable E poll() {
    final Monitor monitor = this.monitor;
    if (monitor.enterIf(notEmpty)) {
      try {
        return extract();
      } finally {
        monitor.leave();
      }
    } else {
      return null;
    }
  }

      } finally {
        monitor.leave();
      }
    } else {
      return null;
    }
  }

  @CanIgnoreReturnValue // pushed down from class to method
  @Override
  public E take() throws InterruptedException {
    final Monitor monitor = this.monitor;
    monitor.enterWhen(notEmpty);
    try {
      return q.poll();
    } finally {
      monitor.leave();
    }
  }

        verifyOccupiedMethodsInAnotherThread(monitor, true, false, 0);
      } finally {
        monitor.leave();
      }
      verifyOccupiedMethodsInCurrentThread(monitor, true, true, 1);
      verifyOccupiedMethodsInAnotherThread(monitor, true, false, 0);
    } finally {
      monitor.leave();
    }
    verifyOccupiedMethodsInCurrentThread(monitor, false, false, 0);

        verifyOccupiedMethodsInAnotherThread(monitor, true, false, 0);
      } finally {
        monitor.leave();
      }
      verifyOccupiedMethodsInCurrentThread(monitor, true, true, 1);
      verifyOccupiedMethodsInAnotherThread(monitor, true, false, 0);
    } finally {
      monitor.leave();
    }
    verifyOccupiedMethodsInCurrentThread(monitor, false, false, 0);

        notifyFailed(shutdownFailure);
      } finally {
        monitor.leave();
        dispatchListenerEvents();
      }
    }
    return this;
  }

  @Override
  public final void awaitRunning() {
    monitor.enterWhenUninterruptibly(hasReachedRunning);
    try {
      checkCurrentState(RUNNING);
    } finally {
      monitor.leave();
    }
  }

  /** @since 28.0 */
  @Override

        notifyFailed(shutdownFailure);
      } finally {
        monitor.leave();
        dispatchListenerEvents();
      }
    }
    return this;
  }

  @Override
  public final void awaitRunning() {
    monitor.enterWhenUninterruptibly(hasReachedRunning);
    try {
      checkCurrentState(RUNNING);
    } finally {
      monitor.leave();
    }
  }

  @Override

    extends UnmodifiableIterator<E> implements ListIterator<E> {
  /** Constructor for use by subclasses. */
  protected UnmodifiableListIterator() {}

  /**
   * Guaranteed to throw an exception and leave the underlying data unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")

  int internalArrayEnd() {
    throw new UnsupportedOperationException();
  }

  @Override
  public abstract boolean contains(@CheckForNull Object object);

  /**
   * Guaranteed to throw an exception and leave the collection unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override

    } else {
      assertNull(task.get(UNEXPECTED_HANG_DELAY_MILLIS, TimeUnit.MILLISECONDS));
    }
  }

  @Override
  protected void tearDown() throws Exception {
    // We don't want to leave stray threads running after each test. At this point, every thread
    // launched by this test is either:
    //
    // (a) Blocked attempting to enter the monitor.
    // (b) Waiting for the single guard to become satisfied.

        }
      } finally {
        monitor.leave();
      }
    }

    void addListener(Listener listener, Executor executor) {
      listeners.addListener(listener, executor);
    }

    void awaitHealthy() {
      monitor.enterWhenUninterruptibly(awaitHealthGuard);
      try {
        checkHealthy();
      } finally {
        monitor.leave();
      }
    }