* @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  public final boolean removeIf(Predicate<? super E> filter) {
    throw new UnsupportedOperationException();
  }

  /**
   * Guaranteed to throw an exception and leave the collection unmodified.
   *

    assertEquals(newArrayList("a", "c", "e"), list);
  }

  public void testRemoveIf() {
    List<String> list = newArrayList("a", "b", "c", "d", "e");
    assertTrue(
        Iterators.removeIf(
            list.iterator(),
            new Predicate<String>() {
              @Override
              public boolean apply(String s) {
                return s.equals("b") || s.equals("d") || s.equals("f");

    assertEquals(newArrayList("a", "c", "e"), list);
  }

  public void testRemoveIf() {
    List<String> list = newArrayList("a", "b", "c", "d", "e");
    assertTrue(
        Iterators.removeIf(
            list.iterator(),
            new Predicate<String>() {
              @Override
              public boolean apply(String s) {
                return s.equals("b") || s.equals("d") || s.equals("f");

   * @return {@code true} if any elements were removed from the iterator
   * @since 2.0
   */
  @CanIgnoreReturnValue
  public static <T extends @Nullable Object> boolean removeIf(
      Iterator<T> removeFrom, Predicate<? super T> predicate) {
    checkNotNull(predicate);
    boolean modified = false;
    while (removeFrom.hasNext()) {
      if (predicate.apply(removeFrom.next())) {