@Override
        public @Nullable Object execute(Iterator<?> iterator) {
          iterator.remove();
          return null;
        }
      };

  private static final IteratorOperation NEXT_METHOD =
      new IteratorOperation() {
        @Override
        public @Nullable Object execute(Iterator<?> iterator) {
          return iterator.next();
        }
      };

import java.util.Iterator;
import java.util.NoSuchElementException;

import org.codelibs.core.exception.ClUnsupportedOperationException;

/**
 * An {@link Iterator} that returns a single value.
 *
 * @author koichik
 * @param <E> the element type
 */
public class SingleValueIterator<E> implements Iterator<E> {

    /** The only value returned by the iterator. */
    protected final E value;

    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 IteratorWithJdkBug6529795<T> implements Iterator<T> {
    Iterator<T> iterator;
    boolean nextThrewException;

    IteratorWithJdkBug6529795(Iterator<T> iterator) {
      this.iterator = iterator;
    }

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

    @Override
    public T next() {
      try {

 * ordinarily difficult to write iterators for. But using this class, one must implement only the
 * {@link #computeNext} method, and invoke the {@link #endOfData} method when appropriate.
 *
 * <p>Another example is an iterator that skips over null elements in a backing iterator. This could
 * be implemented as:
 *
 * {@snippet :
 * public static Iterator<String> skipNulls(final Iterator<String> in) {

    Iterator<Integer> iter =
        new AbstractIterator<Integer>() {
          @Override
          public Integer computeNext() {
            endOfData();
            throw new SomeUncheckedException();
          }
        };
    assertThrows(SomeUncheckedException.class, iter::hasNext);
  }

  public void testCantRemove() {
    Iterator<Integer> iter =

        assertArgumentNotNull("iterator", iterator);

        return () -> new IndexedIterator<>(iterator);
    }

    /**
     * Constructs an instance.
     *
     * @param iterator the iterator (must not be {@literal null})
     */
    public IndexedIterator(final Iterator<T> iterator) {
        assertArgumentNotNull("iterator", iterator);

        this.iterator = iterator;

      }

      @Override
      Iterator<E> elementIterator() {
        throw new AssertionError("should never be called");
      }

      @Override
      Iterator<Entry<E>> entryIterator() {
        Iterator<? extends Entry<? extends E>> iterator1 = multiset1.entrySet().iterator();
        Iterator<? extends Entry<? extends E>> iterator2 = multiset2.entrySet().iterator();

      }

      @Override
      Iterator<E> elementIterator() {
        throw new AssertionError("should never be called");
      }

      @Override
      Iterator<Entry<E>> entryIterator() {
        Iterator<? extends Entry<? extends E>> iterator1 = multiset1.entrySet().iterator();
        Iterator<? extends Entry<? extends E>> iterator2 = multiset2.entrySet().iterator();

        @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;
                        }