@ElementTypesAreNonnullByDefault
public abstract class FinalizableWeakReference<T> extends WeakReference<T>
    implements FinalizableReference {
  /**
   * Constructs a new finalizable weak reference.
   *
   * @param referent to weakly reference
   * @param queue that should finalize the referent
   */
  protected FinalizableWeakReference(@CheckForNull T referent, FinalizableReferenceQueue queue) {
    super(referent, queue.queue);
    queue.cleanUp();

 * specified, the map uses identity ({@code ==}) comparisons instead for keys. Likewise, if {@link
 * #weakValues} was specified, the map uses identity comparisons for values.
 *
 * <p>The view collections of the returned map have <i>weakly consistent iterators</i>. This means
 * that they are safe for concurrent use, but if other threads modify the map after the iterator is
 * created, it is undefined which of these changes, if any, are reflected in that iterator. These

            ? new WeakKeyWeakValueEntry<>(segment.queueForKeys, key, hash)
            : new LinkedWeakKeyWeakValueEntry<>(segment.queueForKeys, key, hash, next);
      }
    }
  }

  /** A weakly referenced value that also has a reference to its containing entry. */
  interface WeakValueReference<K, V, E extends InternalEntry<K, V, E>> {
    /**

      }
      return n;
    } finally {
      monitor.leave();
    }
  }

  /**
   * Returns an iterator over the elements in this queue in proper sequence. The returned {@code
   * Iterator} is a "weakly consistent" iterator that will never throw {@link
   * ConcurrentModificationException}, and guarantees to traverse elements as they existed upon

 *         });
 * }</pre>
 *
 * <p>The returned cache implements all optional operations of the {@link LoadingCache} and {@link
 * Cache} interfaces. The {@code asMap} view (and its collection views) have <i>weakly consistent
 * iterators</i>. This means that they are safe for concurrent use, but if other threads modify the
 * cache after the iterator is created, it is undefined which of these changes, if any, are

  `Two days wrong!' sighed the Hatter.  `I told you butter
wouldn't suit the works!' he added looking angrily at the March
Hare.

  `It was the BEST butter,' the March Hare meekly replied.

  `Yes, but some crumbs must have got in as well,' the Hatter
grumbled:  `you shouldn't have put it in with the bread-knife.'

  The March Hare took the watch and looked at it gloomily:  then

 *       collection. Undefined behavior and bugs will result. It's generally best to avoid using
 *       mutable objects as elements at all, as many users may expect your "immutable" object to be
 *       <i>deeply</i> immutable.
 * </ul>
 *
 * <h4>Performance notes</h4>
 *
 * <ul>
 *   <li>Implementations can be generally assumed to prioritize memory efficiency, then speed of

      monitor.leave();
    }
  }

  /**
   * Returns an iterator over the elements in this queue. The iterator does not return the elements
   * in any particular order. The returned {@code Iterator} is a "weakly consistent" iterator that
   * will never throw {@link ConcurrentModificationException}, and guarantees to traverse elements
   * as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect

 *         });
 * }</pre>
 *
 * <p>The returned cache implements all optional operations of the {@link LoadingCache} and {@link
 * Cache} interfaces. The {@code asMap} view (and its collection views) have <i>weakly consistent
 * iterators</i>. This means that they are safe for concurrent use, but if other threads modify the
 * cache after the iterator is created, it is undefined which of these changes, if any, are

      }
      return n;
    } finally {
      monitor.leave();
    }
  }

  /**
   * Returns an iterator over the elements in this queue in proper sequence. The returned {@code
   * Iterator} is a "weakly consistent" iterator that will never throw {@link
   * ConcurrentModificationException}, and guarantees to traverse elements as they existed upon