as modifying the License.

      You may add Your own copyright statement to Your modifications and
      may provide additional or different license terms and conditions
      for use, reproduction, or distribution of Your modifications, or
      for any such Derivative Works as a whole, provided Your use,
      reproduction, and distribution of the Work otherwise complies with

    List<Integer> toList = Lists.reverse(fromList);
    assertReverseView(fromList, toList);
  }

  private static void assertReverseView(List<Integer> fromList, List<Integer> toList) {
    /* fromList modifications reflected in toList */
    fromList.set(0, 5);
    assertEquals(asList(4, 3, 2, 5), toList);
    fromList.add(6);
    assertEquals(asList(6, 4, 3, 2, 5), toList);
    fromList.add(2, 9);

import java.util.concurrent.atomic.AtomicInteger;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A multiset that supports concurrent modifications and that provides atomic versions of most
 * {@code Multiset} operations (exceptions where noted). Null elements are not supported.
 *
 * <p>See the Guava User Guide article on <a href=

    List<Integer> toList = Lists.reverse(fromList);
    assertReverseView(fromList, toList);
  }

  private static void assertReverseView(List<Integer> fromList, List<Integer> toList) {
    /* fromList modifications reflected in toList */
    fromList.set(0, 5);
    assertEquals(asList(4, 3, 2, 5), toList);
    fromList.add(6);
    assertEquals(asList(6, 4, 3, 2, 5), toList);
    fromList.add(2, 9);

   * implementation-dependent). Furthermore, implementations are not required to support
   * modifications to the entry set at all, and the {@code Entry} instances themselves don't even
   * have methods for modification. See the specific implementation class for more details on how
   * its entry set handles modifications.
   *
   * @return a set of entries representing the data of this multiset
   */
  Set<Entry<E>> entrySet();

import java.util.concurrent.atomic.AtomicInteger;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A multiset that supports concurrent modifications and that provides atomic versions of most
 * {@code Multiset} operations (exceptions where noted). Null elements are not supported.
 *
 * <p>See the Guava User Guide article on <a href=

  // Element Mutation

  @Test
  public void putEdge_existingNodes() {
    assume().that(graphIsMutable()).isTrue();

    // Adding nodes initially for safety (insulating from possible future
    // modifications to proxy methods)
    addNode(N1);
    addNode(N2);

    assertThat(graphAsMutableGraph.putEdge(N1, N2)).isTrue();
  }

  @Test
  public void putEdge_existingEdgeBetweenSameNodes() {

  // Element Mutation

  @Test
  public void putEdge_existingNodes() {
    assume().that(graphIsMutable()).isTrue();

    // Adding nodes initially for safety (insulating from possible future
    // modifications to proxy methods)
    addNode(N1);
    addNode(N2);

    assertThat(graphAsMutableGraph.putEdge(N1, N2)).isTrue();
  }

  @Test
  public void putEdge_existingEdgeBetweenSameNodes() {

  // Element Mutation

  @Test
  public void putEdge_existingNodes() {
    assume().that(graphIsMutable()).isTrue();

    // Adding nodes initially for safety (insulating from possible future
    // modifications to proxy methods)
    addNode(N1);
    addNode(N2);

    assertThat(graphAsMutableGraph.putEdge(N1, N2)).isTrue();
  }

  @Test
  public void putEdge_existingEdgeBetweenSameNodes() {

  @CheckForNull private transient Node<K, V> tail; // the tail for all keys
  private transient Map<K, KeyList<K, V>> keyToKeyList;
  private transient int size;

  /*
   * Tracks modifications to keyToKeyList so that addition or removal of keys invalidates
   * preexisting iterators. This does *not* track simple additions and removals of values
   * that are not the first to be added or last to be removed for their key.