* @return a set of entries representing the data of this multiset
   */
  Set<Entry<E>> entrySet();

  /**
   * An unmodifiable element-count pair for a multiset. The {@link Multiset#entrySet} method returns
   * a view of the multiset whose elements are of this class. A multiset implementation may return
   * Entry instances that are either live "read-through" views to the Multiset, or immutable

   * <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(
      final Multiset<? extends E> multiset1, final Multiset<? extends E> multiset2) {
    checkNotNull(multiset1);
    checkNotNull(multiset2);

      @Override
      protected Multiset<String> create(String[] elements) {
        Multiset<String> multiset1 = LinkedHashMultiset.create();
        Multiset<String> multiset2 = LinkedHashMultiset.create();
        multiset1.add("equalIn1");
        multiset1.add("fewerIn1");
        multiset2.add("equalIn1");
        multiset2.add("fewerIn1", 3);
        multiset2.add("onlyIn2", 2);
        for (int i = 0; i < elements.length; i++) {

      @Override
      protected Multiset<String> create(String[] elements) {
        Multiset<String> multiset1 = LinkedHashMultiset.create();
        Multiset<String> multiset2 = LinkedHashMultiset.create();
        multiset1.add("equalIn1");
        multiset1.add("fewerIn1");
        multiset2.add("equalIn1");
        multiset2.add("fewerIn1", 3);
        multiset2.add("onlyIn2", 2);
        for (int i = 0; i < elements.length; i++) {

    assertThat(multiset).isEmpty();
  }

  public void testRemoveOccurrencesIterableEmpty() {
    Multiset<String> multiset = HashMultiset.create();
    Iterable<String> toRemove = Arrays.asList("a", "b", "a");
    assertFalse(Multisets.removeOccurrences(multiset, toRemove));
    assertTrue(multiset.isEmpty());
  }

  public void testRemoveOccurrencesMultisetEmpty() {

    assertThat(multiset).isEmpty();
  }

  public void testRemoveOccurrencesIterableEmpty() {
    Multiset<String> multiset = HashMultiset.create();
    Iterable<String> toRemove = Arrays.asList("a", "b", "a");
    assertFalse(Multisets.removeOccurrences(multiset, toRemove));
    assertTrue(multiset.isEmpty());
  }

  public void testRemoveOccurrencesMultisetEmpty() {

    assertEquals(
        "multiset.entrySet() iterator.next() returned incorrect entry",
        Multisets.immutableEntry(e0(), 1),
        iterator.next());
    assertFalse(
        "size 1 multiset.entrySet() iterator.hasNext() returned true after next()",
        iterator.hasNext());
    iterator.remove();
    assertTrue(
        "multiset isn't empty after multiset.entrySet() iterator.remove()",
        getMultiset().isEmpty());
  }

  public void testEquals_yes() {
    assertTrue(
        "multiset doesn't equal a multiset with the same elements",
        getMultiset().equals(HashMultiset.create(getSampleElements())));
  }

  public void testEquals_differentSize() {
    Multiset<E> other = HashMultiset.create(getSampleElements());
    other.add(e0());
    assertFalse("multiset equals a multiset with a different size", getMultiset().equals(other));
  }

/**
 * This class provides a skeletal implementation of the {@link Multiset} interface. A new multiset
 * implementation can be created easily by extending this class and implementing the {@link
 * Multiset#entrySet()} method, plus optionally overriding {@link #add(Object, int)} and {@link
 * #remove(Object, int)} to enable modifications to the multiset.
 *

    Multiset<String> c = HashMultiset.create();
    Multiset<String> multiset = ImmutableSortedMultiset.copyOf(c);
    assertTrue(multiset.isEmpty());
  }

  public void testCopyOf_multiset_oneElement() {
    Multiset<String> c = HashMultiset.create(asList("a"));
    Multiset<String> multiset = ImmutableSortedMultiset.copyOf(c);
    assertEquals(HashMultiset.create(asList("a")), multiset);
  }