}

    @Override
    public boolean isEmpty() {
      return !Iterables.any(unfiltered, predicate);
    }

    @Override
    public Iterator<E> iterator() {
      return Iterators.filter(unfiltered.iterator(), predicate);
    }

    @Override
    public boolean remove(@CheckForNull Object element) {
      return contains(element) && unfiltered.remove(element);
    }

    assertFalse(underlying.containsKey("b"));

    Iterator<String> keyIterator = keys.iterator();
    keyIterator.next();
    keyIterator.remove();
    assertFalse(underlying.containsKey("c"));

    Collection<String> values = map.values();
    values.remove("4");
    assertFalse(underlying.containsKey("d"));

    Iterator<String> valueIterator = values.iterator();
    valueIterator.next();
    valueIterator.remove();

  @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());
  }

The [strings] package adds several functions that work with iterators:
- [Lines] returns an iterator over
  the newline-terminated lines in the string s.
- [SplitSeq] returns an iterator over
  all substrings of s separated by sep.
- [SplitAfterSeq] returns an iterator
  over substrings of s split after each instance of sep.
- [FieldsSeq] returns an iterator over
  substrings of s split around runs of whitespace characters,
  as defined by unicode.IsSpace.

    }

    /**
     * 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();
    }

    /**

    assertThrows(NoSuchElementException.class, () -> iterator.next());
    assertThrows(IllegalStateException.class, () -> iterable.iterator());
  }

  public void testOf_one() {
    Iterable<String> iterable = MinimalIterable.of("a");
    Iterator<String> iterator = iterable.iterator();
    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertFalse(iterator.hasNext());

   */
  static class IteratorWithSunJavaBug6529795<T> implements Iterator<T> {
    Iterator<T> iterator;
    boolean nextThrewException;

    IteratorWithSunJavaBug6529795(Iterator<T> iterator) {
      this.iterator = iterator;
    }

    @Override
    public boolean hasNext() {
      return iterator.hasNext();
    }

    @Override
    public T next() {
      try {

    Iterator<String> iterator = asList("a", "b", "a").iterator();
    Multiset<String> multiset = ImmutableMultiset.copyOf(iterator);
    assertEquals(HashMultiset.create(asList("a", "b", "a")), multiset);
  }

  public void testCopyOf_iteratorContainingNull() {
    Iterator<@Nullable String> iterator =
        Arrays.<@Nullable String>asList("a", null, "b").iterator();
    assertThrows(

    assertEquals("b", iterator.previous());
    assertThrows(UnsupportedOperationException.class, () -> iterator.add("c"));
  }

  @SuppressWarnings("DoNotCall")
  public void testSet() {
    ListIterator<String> iterator = create();

    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertEquals("b", iterator.next());
    assertEquals("b", iterator.previous());

          return AsMap.this;
        }

        @Override
        public Iterator<Entry<K, Collection<V>>> iterator() {
          return new AbstractIterator<Entry<K, Collection<V>>>() {
            final Iterator<Entry<K, Collection<V>>> backingIterator =
                unfiltered.asMap().entrySet().iterator();

            @Override
            @CheckForNull