*/
@GwtCompatible
public final class HashMultiset<E extends @Nullable Object> extends AbstractMapBasedMultiset<E> {

  /** Creates a new, empty {@code HashMultiset} using the default initial capacity. */
  public static <E extends @Nullable Object> HashMultiset<E> create() {
    return create(ObjectCountHashMap.DEFAULT_SIZE);
  }

  /**
   * Creates a new, empty {@code HashMultiset} with the specified expected number of distinct

 * @since 2.0
 */
@GwtCompatible
public final class HashMultiset<E extends @Nullable Object> extends AbstractMapBasedMultiset<E> {

  /** Creates a new, empty {@code HashMultiset} using the default initial capacity. */
  public static <E extends @Nullable Object> HashMultiset<E> create() {
    return new HashMultiset<>();
  }

  /**
   * Creates a new, empty {@code HashMultiset} with the specified expected number of distinct
   * elements.

  @Param({"0", "1", "16", "256", "4096", "65536"})
  int size;

  LinkedHashMultiset<Object> linkedHashMultiset;
  HashMultiset<Object> hashMultiset;

  // TreeMultiset requires a Comparable element.
  TreeMultiset<Integer> treeMultiset;

  @BeforeExperiment
  void setUp() {
    hashMultiset = HashMultiset.create(size);
    linkedHashMultiset = LinkedHashMultiset.create(size);
    treeMultiset = TreeMultiset.create();

    return new TestStringMultisetGenerator() {
      @Override
      protected Multiset<String> create(String[] elements) {
        return HashMultiset.create(asList(elements));
      }
    };
  }

  public void testCreate() {
    Multiset<String> multiset = HashMultiset.create();
    multiset.add("foo", 2);
    multiset.add("bar");
    assertEquals(3, multiset.size());
    assertEquals(2, multiset.count("foo"));
  }

  int[] queries = new int[ARRAY_SIZE];

  @BeforeExperiment
  void setUp() {
    Random random = new Random();
    multisets.clear();
    for (int i = 0; i < ARRAY_SIZE; i++) {
      HashMultiset<Integer> multiset = HashMultiset.<Integer>create();
      multisets.add(multiset);
      queries[i] = random.nextInt();
      multiset.add(queries[i]);
    }
  }

  @Benchmark
  int add(int reps) {
    int tmp = 0;

  int[] queries = new int[ARRAY_SIZE];

  @BeforeExperiment
  void setUp() {
    Random random = new Random();
    multisets.clear();
    for (int i = 0; i < ARRAY_SIZE; i++) {
      HashMultiset<Integer> multiset = HashMultiset.<Integer>create();
      multisets.add(multiset);
      queries[i] = random.nextInt();
      multiset.add(queries[i]);
    }
  }

  @Benchmark
  int add(int reps) {
    int tmp = 0;

    return new TestStringMultisetGenerator() {
      @Override
      protected Multiset<String> create(String[] elements) {
        return HashMultiset.create(asList(elements));
      }
    };
  }

  public void testCreate() {
    Multiset<String> multiset = HashMultiset.create();
    multiset.add("foo", 2);
    multiset.add("bar");
    assertEquals(3, multiset.size());
    assertEquals(2, multiset.count("foo"));
  }

   * multiset1}, with repeated occurrences of the same element appearing consecutively.
   *
   * <p>Results are undefined if {@code multiset1} and {@code multiset2} are based on different
   * equivalence relations (as {@code HashMultiset} and {@code TreeMultiset} are).
   *
   * @since 14.0
   */
  public static <E extends @Nullable Object> Multiset<E> union(
      Multiset<? extends E> multiset1, Multiset<? extends E> multiset2) {

   * multiset1}, with repeated occurrences of the same element appearing consecutively.
   *
   * <p>Results are undefined if {@code multiset1} and {@code multiset2} are based on different
   * equivalence relations (as {@code HashMultiset} and {@code TreeMultiset} are).
   *
   * @since 14.0
   */
  public static <E extends @Nullable Object> Multiset<E> union(
      Multiset<? extends E> multiset1, Multiset<? extends E> multiset2) {

  @Generates
  static <E> Multiset<E> generateMultiset(@Nullable E freshElement) {
    return generateHashMultiset(freshElement);
  }

  @Generates
  static <E> HashMultiset<E> generateHashMultiset(@Nullable E freshElement) {
    HashMultiset<E> multiset = HashMultiset.create();
    multiset.add(freshElement);
    return multiset;
  }

  @Generates