}

    @Override
    public E getFirst() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.getFirst();
    }

    @Override
    public E getLast() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.getLast();
    }

    @Override
    public @Nullable E peekFirst() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.peekFirst();
    }

    assertEquals("c", Iterables.getLast(list));
  }

  public void testGetLast_emptyList() {
    List<String> list = emptyList();
    assertThrows(NoSuchElementException.class, () -> Iterables.getLast(list));
  }

  public void testGetLast_sortedSet() {
    SortedSet<String> sortedSet = ImmutableSortedSet.of("b", "c", "a");
    assertEquals("c", Iterables.getLast(sortedSet));
  }

    }

    @Override
    public boolean hasNext() {
      return !stack.isEmpty();
    }

    @Override
    public T next() {
      Iterator<T> itr = stack.getLast(); // throws NSEE if empty
      T result = checkNotNull(itr.next());
      if (!itr.hasNext()) {
        stack.removeLast();
      }
      Iterator<T> childItr = children(result).iterator();

    assertEquals("foo", Iterators.getLast(iterator, "bar"));
  }

  public void testGetLast_withDefault_empty() {
    Iterator<String> iterator = emptyIterator();
    assertEquals("bar", Iterators.getLast(iterator, "bar"));
  }

  public void testGetLast_withDefault_empty_null() {
    Iterator<String> iterator = emptyIterator();
    assertNull(Iterators.<@Nullable String>getLast(iterator, null));
  }

    assertEquals("foo", Iterators.getLast(iterator, "bar"));
  }

  public void testGetLast_withDefault_empty() {
    Iterator<String> iterator = emptyIterator();
    assertEquals("bar", Iterators.getLast(iterator, "bar"));
  }

  public void testGetLast_withDefault_empty_null() {
    Iterator<String> iterator = emptyIterator();
    assertNull(Iterators.<@Nullable String>getLast(iterator, null));
  }

   *
   * @throws NullPointerException if the last element is null; if this is a possibility, use {@link
   *     Iterables#getLast} instead.
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final Optional<@NonNull E> last() {
    // Iterables#getLast was inlined here so we don't have to throw/catch a NSEE

    // TODO(kevinb): Support a concurrently modified collection?

    private final boolean positiveBoundedAbove;

    private final int size;

    ComplementRanges() {
      this.positiveBoundedBelow = ranges.get(0).hasLowerBound();
      this.positiveBoundedAbove = Iterables.getLast(ranges).hasUpperBound();

      int size = ranges.size() - 1;
      if (positiveBoundedBelow) {
        size++;
      }
      if (positiveBoundedAbove) {
        size++;
      }

   * @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

    @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();

    @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();