private final ImmutableList<String> keys;
    private final Random random = new Random();

    private MutateTask(ConcurrentHashMultiset<String> multiset, ImmutableList<String> keys) {
      this.multiset = multiset;
      this.keys = keys;
    }

    @Override
    public int[] call() throws Exception {
      int iterations = 100000;
      int nKeys = keys.size();
      int[] deltas = new int[nKeys];

          map.put(element, element);
        }
        return map;
      }
    },
    UnmodHM {
      @Override
      Map<Element, Element> create(Collection<Element> keys) {
        return Collections.unmodifiableMap(Hash.create(keys));
      }
    },
    SyncHM {
      @Override
      Map<Element, Element> create(Collection<Element> keys) {
        return Collections.synchronizedMap(Hash.create(keys));
      }

  }

  /**
   * Uses a hash table to map keys to value collections.
   *
   * <p>The collections returned by {@link Multimap#keySet()}, {@link Multimap#keys()}, and {@link
   * Multimap#asMap()} will iterate through the keys in the order that they were first added to the
   * multimap, save that if all values associated with a key are removed and then the key is added
   * back into the multimap, that key will come last in the key iteration order.
   */

          .addEqualityGroup(cache.asMap().keySet(), keys)
          .addEqualityGroup(ImmutableSet.of())
          .testEquals();
      assertEquals(WARMUP_SIZE, keys.size());
      for (int i = WARMUP_MIN; i < WARMUP_MAX; i++) {
        Object key = warmed.get(i - WARMUP_MIN).getKey();
        assertTrue(keys.contains(key));
        assertTrue(keys.remove(key));
        assertFalse(keys.remove(key));
        assertFalse(keys.contains(key));

     * cause {@link #build} to fail.
     *
     * @since 19.0
     */
    @CanIgnoreReturnValue
    @Override
    public Builder<K, V> put(Entry<? extends K, ? extends V> entry) {
      super.put(entry);
      return this;
    }

    /**
     * Associates all of the given map's keys and values in the built bimap. Duplicate keys or

  public void testPutPresentKeyPropagatesToGet() {
    List<K> keys = Helpers.copyToList(multimap().keySet());
    for (K key : keys) {
      resetContainer();

      int size = getNumElements();

      Collection<V> collection = multimap().get(key);
      Collection<V> expectedCollection = Helpers.copyToList(collection);

      multimap().put(key, v3());
      expectedCollection.add(v3());

 * Null row keys, columns keys, and values are not supported.
 *
 * <p>Lookups by row key are often faster than lookups by column key, because the data is stored in
 * a {@code Map<R, Map<C, V>>}. A method call like {@code column(columnKey).get(rowKey)} still runs
 * quickly, since the row key is provided. However, {@code column(columnKey).size()} takes longer,

  SortedMap<K, V> create(Object... elements);

  /**
   * Returns an entry with a key less than the keys of the {@link #samples()} and less than the key
   * of {@link #belowSamplesGreater()}.
   */
  Entry<K, V> belowSamplesLesser();

  /**
   * Returns an entry with a key less than the keys of the {@link #samples()} but greater than the
   * key of {@link #belowSamplesLesser()}.
   */
  Entry<K, V> belowSamplesGreater();

  /**

    int[] entries = requireEntries();
    @Nullable Object[] keys = requireKeys();
    @Nullable Object[] values = requireValues();
    int srcIndex = size() - 1;
    if (dstIndex < srcIndex) {
      // move last entry to deleted spot
      Object key = keys[srcIndex];
      keys[dstIndex] = key;
      values[dstIndex] = values[srcIndex];
      keys[srcIndex] = null;
      values[srcIndex] = null;

  }

  @Override
  public void invalidate(Object key) {
    throw new UnsupportedOperationException();
  }

  /** @since 11.0 */
  @Override
  // For discussion of <? extends Object>, see getAllPresent.
  public void invalidateAll(Iterable<? extends Object> keys) {
    for (Object key : keys) {
      invalidate(key);
    }
  }

  @Override
  public void invalidateAll() {