public abstract class ForwardingMapEntry<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingObject implements Map.Entry<K, V> {
  // TODO(lowasser): identify places where thread safety is actually lost

  /** Constructor for use by subclasses. */
  protected ForwardingMapEntry() {}

  @Override
  protected abstract Entry<K, V> delegate();

  @Override
  @ParametricNullness
  public K getKey() {

public abstract class ForwardingMapEntry<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingObject implements Map.Entry<K, V> {
  // TODO(lowasser): identify places where thread safety is actually lost

  /** Constructor for use by subclasses. */
  protected ForwardingMapEntry() {}

  @Override
  protected abstract Entry<K, V> delegate();

  @Override
  @ParametricNullness
  public K getKey() {

types (such as multimap and multiset), immutable collections, a graph library,
and utilities for concurrency, I/O, hashing, primitives, strings, and more! It
is widely used on most Java projects within Google, and widely used by many
other companies as well.



Guava comes in two flavors:

*   The JRE flavor requires JDK 1.8 or higher.
*   If you need support for Android, use

      if (childItr.hasNext()) {
        stack.addLast(childItr);
      }
      return result;
    }
  }

  /**
   * Returns an unmodifiable iterable over the nodes in a tree structure, using post-order
   * traversal. That is, each node's subtrees are traversed before the node itself is returned.
   *
   * <p>No guarantees are made about the behavior of the traversal when nodes change while iteration