void executeAndCompare(ListIterator<E> reference, Iterator<E> target) {
          internalExecuteAndCompare(reference, target, NEXT_METHOD);
        }
      };
  Stimulus<E, Iterator<E>> remove =
      new Stimulus<E, Iterator<E>>("remove") {
        @Override
        void executeAndCompare(ListIterator<E> reference, Iterator<E> target) {
          internalExecuteAndCompare(reference, target, REMOVE_METHOD);
        }
      };

    if (reference == null) {
      throw new NullPointerException();
    }
    return reference;
  }

  /**
   * Ensures that an object reference passed as a parameter to the calling method is not null.
   *
   * @param reference an object reference
   * @param errorMessage the exception message to use if the check fails; will be converted to a

    Integer[] array1Tmp = array1;
    Object[] reference = list.toArray(array1Tmp);

    Object[] target = ObjectArrays.toArrayImpl(list, array2);

    assertEquals(reference.getClass(), target.getClass());
    assertTrue(Arrays.equals(reference, target));
    assertTrue(Arrays.equals(reference, target));

    Object[] expectedArray1 = expectModify ? reference : starting;

        void executeAndCompare(ListIterator<E> reference, Iterator<E> target) {
          internalExecuteAndCompare(reference, target, NEXT_METHOD);
        }
      };
  Stimulus<E, Iterator<E>> remove =
      new Stimulus<E, Iterator<E>>("remove") {
        @Override
        void executeAndCompare(ListIterator<E> reference, Iterator<E> target) {
          internalExecuteAndCompare(reference, target, REMOVE_METHOD);
        }
      };

        map.put(keyOne, valueOne);
        InternalEntry<Object, Object, ?> entry = segment.getEntry(keyOne, hashOne);

        @SuppressWarnings("unchecked")
        Reference<Object> reference = (Reference<Object>) entry;
        reference.enqueue();

        map.put(keyTwo, valueTwo);
        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));
        assertNull(map.get(keyOne));

        map.put(keyOne, valueOne);
        InternalEntry<Object, Object, ?> entry = segment.getEntry(keyOne, hashOne);

        @SuppressWarnings("unchecked")
        Reference<Object> reference = (Reference<Object>) entry;
        reference.enqueue();

        map.put(keyTwo, valueTwo);
        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));
        assertNull(map.get(keyOne));

/**
 * An immutable object that may contain a non-null reference to another object. Each instance of
 * this type either contains a non-null reference, or contains nothing (in which case we say that
 * the reference is "absent"); it is never said to "contain {@code null}".
 *
 * <p>A non-null {@code Optional<T>} reference can be used as a replacement for a nullable {@code T}

      }
    }
  }

  /** A weakly referenced value that also has a reference to its containing entry. */
  interface WeakValueReference<K, V, E extends InternalEntry<K, V, E>> {
    /**
     * Returns the current value being referenced, or {@code null} if there is none (e.g. because

 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Functions {
  private Functions() {}

  /**
   * A function equivalent to the method reference {@code Object::toString}, for users not yet using
   * Java 8. The function simply invokes {@code toString} on its argument and returns the result. It
   * throws a {@link NullPointerException} on null input.
   *

    TreeMultiset<E> multiset = create();
    Iterables.addAll(multiset, elements);
    return multiset;
  }

  private final transient Reference<AvlNode<E>> rootReference;
  private final transient GeneralRange<E> range;
  private final transient AvlNode<E> header;

  TreeMultiset(Reference<AvlNode<E>> rootReference, GeneralRange<E> range, AvlNode<E> endLink) {
    super(range.comparator());
    this.rootReference = rootReference;