assertFalse(getMap().entrySet().iterator().hasNext());
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)
  public void testClearConcurrentWithEntrySetIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<Entry<K, V>> iterator = getMap().entrySet().iterator();
          getMap().clear();

              throw new NoSuchElementException();
            }
            return array[i++];
          }
        };

    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertThrows(UnsupportedOperationException.class, () -> iterator.remove());
  }

    multimap.put("foo", 2);
    multimap.put("bar", 3);
    Collection<Entry<String, Integer>> entries = multimap.entries();
    Iterator<Entry<String, Integer>> iterator = entries.iterator();
    Entry<String, Integer> entrya = iterator.next();
    Entry<String, Integer> entryb = iterator.next();

    assertEquals(2, (int) multimap.get("foo").set(0, 4));
    assertFalse(multimap.containsEntry("foo", 2));

package com.google.common.collect;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.annotations.GwtCompatible;
import java.util.Iterator;
import org.jspecify.annotations.Nullable;

/**
 * An iterator that transforms a backing iterator; for internal use. This avoids the object overhead
 * of constructing a {@link com.google.common.base.Function Function} for internal methods.
 *
 * @author Louis Wasserman

    Set<Entry<Integer, String>> entries = map.entrySet();
    Iterator<Entry<Integer, String>> iterator = entries.iterator();
    Entry<Integer, String> entry = iterator.next();
    entry.setValue("two"); // changes the iterator's current entry value
    assertEquals("two", map.get(1));
    assertEquals(Integer.valueOf(1), map.inverse().get("two"));
    iterator.remove(); // removes the updated entry
    assertTrue(map.isEmpty());
  }

    Iterator<E> iterator = collection.iterator();
    assertSetCount(e3(), 1);
    assertThrows(ConcurrentModificationException.class, iterator::next);
  }

  @CollectionFeature.Require({SUPPORTS_ADD, FAILS_FAST_ON_CONCURRENT_MODIFICATION})
  public void testSetCountZeroToOneConcurrentWithEntrySetIteration() {
    Iterator<Entry<E>> iterator = getMultiset().entrySet().iterator();

    } catch (IllegalArgumentException e) {
      return emptySet(comparator());
    }
  }

  @Nullable E higher(E e) {
    checkNotNull(e);
    Iterator<E> iterator = tailSet(e).iterator();
    while (iterator.hasNext()) {
      E higher = iterator.next();
      if (comparator().compare(e, higher) < 0) {
        return higher;
      }
    }
    return null;
  }

  public @Nullable E ceiling(E e) {

      return;
    }

    Set<Entry<K, V>> entrySet = map.entrySet();
    Iterator<Entry<K, V>> iterator = entrySet.iterator();
    if (supportsIteratorRemove) {
      int initialSize = map.size();
      Entry<K, V> entry = iterator.next();
      Entry<K, V> entryCopy = mapEntry(entry.getKey(), entry.getValue());

      iterator.remove();
      assertEquals(initialSize - 1, map.size());

      return original.size();
    }

    @Override
    public Collection<V> values() {
      return original.values();
    }

    @Override
    Iterator<Cell<C, R, V>> cellIterator() {
      return Iterators.transform(original.cellSet().iterator(), Tables::transposeCell);
    }
  }

  private static <
          R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>

 *
 * @author Mick Killianey
 * @since 2.0
 */
@DoNotMock("Use Iterators.peekingIterator")
@GwtCompatible
public interface PeekingIterator<E extends @Nullable Object> extends Iterator<E> {
  /**
   * Returns the next element in the iteration, without advancing the iteration.
   *
   * <p>Calls to {@code peek()} should not change the state of the iteration, except that it