return () ->
        new AbstractIterator<T>() {
          private final Iterator<? extends Optional<? extends T>> iterator =
              checkNotNull(optionals.iterator());

          @Override
          protected @Nullable T computeNext() {
            while (iterator.hasNext()) {
              Optional<? extends T> optional = iterator.next();
              if (optional.isPresent()) {
                return optional.get();

        @Override
        public Set<Entry<Object, Object>> entrySet() {
            return new AbstractImmutableSet<>() {
                @Override
                public Iterator<Entry<Object, Object>> iterator() {
                    return new Iterator<>() {
                        @Override
                        public boolean hasNext() {
                            return false;
                        }

    for (Class<? super T> itf : allInterfaceClasses) {
      Iterator<Class<?>> iterator = interfaceClasses.iterator();
      boolean addToSet = true;
      while (iterator.hasNext()) {
        Class<?> current = iterator.next();
        if (current == itf || itf.isAssignableFrom(current)) {
          // Skip any super interface of the ones that are already included.

  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testKeySetIteratorRemove() {
    int initialSize = getNumElements();
    Iterator<K> iterator = getMap().keySet().iterator();
    iterator.next();
    iterator.remove();
    assertEquals(initialSize - 1, getMap().size());
    assertEquals(initialSize - 1, getMap().inverse().size());
  }

      Comparator<? super E> comparator, Iterator<? extends E> elements) {
    checkNotNull(comparator);
    return new Builder<E>(comparator).addAll(elements).build();
  }

  /**
   * Returns an immutable sorted multiset containing the given elements sorted by the given {@code
   * Comparator}. This method iterates over {@code elements} at most once.
   *

    }

    /**
     * Returns an iterator over the elements in this set. The elements are
     * returned in no particular order.
     *
     * @return an Iterator over the elements in this set.
     * @see ConcurrentModificationException
     */
    @Override
    public Iterator<E> iterator() {
        return map.keySet().iterator();
    }

    /**

        @Nonnull
        public Optional<Lifecycle> lookup(String id) {
            return getDelegate().lookup(id);
        }

        @Override
        public Iterator<Lifecycle> iterator() {
            return getDelegate().iterator();
        }

        protected LifecycleRegistry getDelegate() {
            return lifecycleRegistry;
        }

        @Override

        @Nonnull
        public Optional<Lifecycle> lookup(String id) {
            return getDelegate().lookup(id);
        }

        @Override
        public Iterator<Lifecycle> iterator() {
            return getDelegate().iterator();
        }

        protected LifecycleRegistry getDelegate() {
            return lifecycleRegistry;
        }

        @Override

     * @return An iterator of URL objects for the resources. If no resources are found, the iterator will be empty.
     *         Resources that the class loader does not have access to will not be included.
     * @see java.lang.ClassLoader#getResources(String)
     */
    public static Iterator<URL> getResources(final String name) {
        assertArgumentNotEmpty("name", name);

  }

  /**
   * Returns an iterator over the cache's current entries. This iterator doesn't throw
   * `ConcurrentModificationException`, but if new entries are added while iterating, those new
   * entries will not be returned by the iterator. If existing entries are removed during iteration,
   * they will be absent (unless they were already returned).
   *