}

  @Override
  public boolean contains(@Nullable Object element) {
    return count(element) > 0;
  }

  // Modification Operations
  @CanIgnoreReturnValue
  @Override
  public final boolean add(@ParametricNullness E element) {
    add(element, 1);
    return true;
  }

  @CanIgnoreReturnValue
  @Override
  public int add(@ParametricNullness E element, int occurrences) {
    throw new UnsupportedOperationException();

  final transient E element;

  SingletonImmutableSet(E element) {
    this.element = Preconditions.checkNotNull(element);
  }

  @Override
  public int size() {
    return 1;
  }

  @Override
  public boolean contains(@Nullable Object target) {
    return element.equals(target);
  }

  @Override
  public UnmodifiableIterator<E> iterator() {

                Map<Object, Object> context = Collections.emptyMap();

                for (Plugin element : src) {
                    Object key = getPluginKey(element);
                    managedPlugins.put(key, element);
                }

                for (Plugin element : tgt) {
                    Object key = getPluginKey(element);
                    Plugin managedPlugin = managedPlugins.get(key);

                for (PluginExecution element : tgt) {
                    Object key = getPluginExecutionKey(element);
                    merged.put(key, element);
                }

                for (PluginExecution element : src) {
                    Object key = getPluginExecutionKey(element);
                    PluginExecution existing = merged.get(key);

    final int hash;

    Element(int hash) {
      this.hash = hash;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      return this == obj || (obj instanceof Element && ((Element) obj).hash == hash);
    }

    @Override
    public int hashCode() {
      return hash;
    }

    @Override
    public int compareTo(Element that) {

  public void testElement_empty() {
    assertThrows(NoSuchElementException.class, () -> getQueue().element());
    expectUnchanged();
  }

  @CollectionSize.Require(ONE)
  public void testElement_size1() {
    assertEquals("size1Queue.element() should return first element", e0(), getQueue().element());
    expectUnchanged();
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  @CollectionSize.Require(SEVERAL)

 */
final class SingletonImmutableList<E> extends ForwardingImmutableList<E> {
  private final transient List<E> delegate;
  private final E element;

  SingletonImmutableList(E element) {
    this.delegate = singletonList(checkNotNull(element));
    this.element = element;
  }

  @Override
  List<E> delegateList() {
    return delegate;
  }

  @Override
  void setCountCheckReturnValue(E element, int count) {
    assertEquals(
        "multiset.setCount() should return the old count",
        getMultiset().count(element),
        setCount(element, count));
  }

  @Override
  void setCountNoCheckReturnValue(E element, int count) {
    setCount(element, count);
  }

  @CanIgnoreReturnValue
  private int setCount(E element, int count) {

     *
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        StringBuilder ret = new StringBuilder();
        for (final byte element : this.b) {
            final int n = element & 0xff;
            if (n <= 0x0f) {
                ret.append("0");
            }
            ret.append(Integer.toHexString(n));
        }
        return ret.toString();
    }

  public int count(@Nullable Object element) {
    return delegate().count(element);
  }

  @CanIgnoreReturnValue
  @Override
  public int add(@ParametricNullness E element, int occurrences) {
    return delegate().add(element, occurrences);
  }

  @CanIgnoreReturnValue
  @Override
  public int remove(@Nullable Object element, int occurrences) {
    return delegate().remove(element, occurrences);
  }

  @Override