this.listeners.add(listener);
    }

    public void removeProjectExecutionListener(ProjectExecutionListener listener) {
        this.listeners.remove(listener);
    }

  public boolean isEmpty() {
    return size() == 0;
  }

  @Override
  public void clear() {
    Iterators.clear(cellSet().iterator());
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable V remove(@Nullable Object rowKey, @Nullable Object columnKey) {
    Map<C, V> row = safeGet(rowMap(), rowKey);
    return (row == null) ? null : Maps.safeRemove(row, columnKey);
  }

  @CanIgnoreReturnValue
  @Override

  // TODO(b/192446998): Remove this override after tools understand nullness better.
  public @Nullable V put(K key, @ParametricNullness V value) {
    return super.put(key, value);
  }

  @CanIgnoreReturnValue
  @Override
  @SuppressWarnings("RedundantOverride") // b/192446478: RedundantOverride ignores some annotations.
  // TODO(b/192446998): Remove this override after tools understand nullness better.

     *
     * @param key the key under which to store the session data, must not be {@code null}
     * @param value the data to associate with the key, may be {@code null} to remove the mapping
     */
    <T> void set(@Nonnull Key<T> key, @Nullable T value);

    /**
     * Associates the specified session data with the given key if the key is currently mapped to the given value. This

 *
 * <p>This enum is GWT compatible.
 *
 * @author Chris Povirk
 */
@GwtCompatible
public enum IteratorFeature {
  /** Support for {@link Iterator#remove()}. */
  SUPPORTS_REMOVE,
  /**
   * Support for {@link ListIterator#add(Object)}; ignored for plain {@link Iterator}
   * implementations.
   */
  SUPPORTS_ADD,
  /**

     * @param artifact the artifact definition
     * @param localRepository the local repository to install into
     * @throws ArtifactInstallationException if an error occurred installing the artifact
     * @deprecated to be removed before 2.0 after the install/deploy plugins use the alternate
     *             method
     */
    @Deprecated
    void install(String basedir, String finalName, Artifact artifact, ArtifactRepository localRepository)

     * @param rootProject The root project that is being built.
     */
    void applyResumptionData(MavenExecutionRequest request, MavenProject rootProject);

    /**
     * Removes previously stored resumption data.
     * @param rootProject The root project that is being built.
     */
    void removeResumptionData(MavenProject rootProject);

          iterator.next();
          iterator.remove();
        });

    Set<Entry<Integer, String>> entries = unmod.entrySet();
    assertThrows(
        UnsupportedOperationException.class,
        () -> {
          Iterator<Entry<Integer, String>> iterator = entries.iterator();
          iterator.next();
          iterator.remove();
        });
    {

    String[] strings = this.strings;
    for (int i = 0; i < reps; i++) {
      for (int j = 0; j < capacity; j++) {
        queue.add(strings[j]);
      }
      for (int j = 0; j < capacity; j++) {
        queue.remove();
      }
    }
  }

      }

      <E extends @Nullable Object> void push(List<E> stack, E value) {
        stack.add(value);
      }

      <E extends @Nullable Object> E pop(List<E> stack) {
        return stack.remove(stack.size() - 1);
      }
    };

    abstract <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>
        A result(Collector<T, A, R> collector, Iterable<T> inputs);
  }