public void testGetLast_basic() {
    List<String> list = newArrayList();
    list.add("a");
    list.add("b");
    assertEquals("b", getLast(list.iterator()));
  }

  public void testGetLast_exception() {
    List<String> list = newArrayList();
    try {
      getLast(list.iterator());
      fail();
    } catch (NoSuchElementException expected) {
    }
  }

    @Override
    public E getFirst() {
      synchronized (mutex) {
        return delegate().getFirst();
      }
    }

    @Override
    public E getLast() {
      synchronized (mutex) {
        return delegate().getLast();
      }
    }

    @Override
    @CheckForNull
    public E peekFirst() {
      synchronized (mutex) {
        return delegate().peekFirst();

  public void testGetLast_basic() {
    List<String> list = newArrayList();
    list.add("a");
    list.add("b");
    assertEquals("b", getLast(list.iterator()));
  }

  public void testGetLast_exception() {
    List<String> list = newArrayList();
    try {
      getLast(list.iterator());
      fail();
    } catch (NoSuchElementException expected) {
    }
  }

   * @return the last element of {@code iterator}
   * @since 3.0
   */
  @ParametricNullness
  public static <T extends @Nullable Object> T getLast(
      Iterator<? extends T> iterator, @ParametricNullness T defaultValue) {
    return iterator.hasNext() ? getLast(iterator) : defaultValue;
  }

  /**
   * Calls {@code next()} on {@code iterator}, either {@code numberToAdvance} times or until {@code

   * @return the last element of {@code iterator}
   * @since 3.0
   */
  @ParametricNullness
  public static <T extends @Nullable Object> T getLast(
      Iterator<? extends T> iterator, @ParametricNullness T defaultValue) {
    return iterator.hasNext() ? getLast(iterator) : defaultValue;
  }

  /**
   * Calls {@code next()} on {@code iterator}, either {@code numberToAdvance} times or until {@code