private static final int ARRAY_SIZE = 0x10000;
  List<Multiset<Integer>> multisets = new ArrayList<>(0x10000);
  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();

        new ImmutableMultiset.Builder<String>().addCopies("x", 10).build();
    multiset.addAll(adds);
    assertEquals(1, addCalls.get());
  }

  public void testRemoveUnsupported() {
    Multiset<String> multiset = new NoRemoveMultiset<>();
    multiset.add("a");
    assertThrows(UnsupportedOperationException.class, () -> multiset.remove("a"));
    assertTrue(multiset.contains("a"));
  }

    resetContainer(mapEntry(k0(), v0()), mapEntry(k0(), v1()), mapEntry(k1(), v0()));
    Multiset<K> keys = multimap().keys();
    assertEquals(2, keys.count(k0()));
    assertEquals(1, keys.count(k1()));
    assertEquals(3, keys.size());
    assertContainsAllOf(keys, k0(), k1());
    assertContainsAllOf(
        keys.entrySet(), Multisets.immutableEntry(k0(), 2), Multisets.immutableEntry(k1(), 1));
  }

  @MapFeature.Require(ALLOWS_NULL_KEY_QUERIES)

   */
  protected class StandardElementSet extends Multisets.ElementSet<E> {
    /** Constructor for use by subclasses. */
    public StandardElementSet() {}

    @Override
    Multiset<E> multiset() {
      return ForwardingMultiset.this;
    }

    @Override
    public Iterator<E> iterator() {
      return Multisets.elementIterator(multiset().entrySet().iterator());
    }
  }

  /**

    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());
  }

    getMultiset().elementSet().clear();
    assertEmpty(getMultiset());
  }

  /**
   * Returns {@link Method} instances for the read tests that assume multisets support duplicates so
   * that the test of {@code Multisets.forSet()} can suppress them.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection
  public static List<Method> getElementSetDuplicateInitializingMethods() {
    return asList(

        () -> TreeMultiset.create(comparator),
        (multiset, t) ->
            multiset.add(checkNotNull(elementFunction.apply(t)), countFunction.applyAsInt(t)),
        (multiset1, multiset2) -> {
          multiset1.addAll(multiset2);
          return multiset1;
        },
        (Multiset<E> multiset) -> copyOfSortedEntries(comparator, multiset.entrySet()));
  }

  /**

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multiset;
import com.google.common.collect.testing.SampleElements;
import com.google.common.collect.testing.SampleElements.Strings;
import java.util.List;
import org.jspecify.annotations.NullMarked;

/**
 * Create multisets of strings for tests.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked

  private static final int ARRAY_SIZE = 0x10000;
  List<Multiset<Integer>> multisets = new ArrayList<>(0x10000);
  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 for every occurrence in {@code c}, see {@link Multisets#retainOccurrences(Multiset,
   * Multiset)}.
   *
   * <p>This method refines {@link Collection#retainAll} to further specify that it <b>may not</b>
   * throw an exception in response to any of {@code elements} being null or of the wrong type.
   *
   * @see Multisets#retainOccurrences(Multiset, Multiset)
   */
  @CanIgnoreReturnValue