Map<Element, Element> map = new MapMaker().concurrencyLevel(1).makeMap();
        for (Element element : keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    MapMaker16 {
      @Override
      Map<Element, Element> create(Collection<Element> keys) {
        Map<Element, Element> map = new MapMaker().concurrencyLevel(16).makeMap();
        for (Element element : keys) {

      fail();
    } catch (IllegalStateException expected) {
    }
  }

  public void testReturnsPlainConcurrentHashMapWhenPossible() {
    Map<?, ?> map = new MapMaker().initialCapacity(5).makeMap();
    assertTrue(map instanceof ConcurrentHashMap);
  }

  private static final String TEST_KEY = "test key";
  private static final String TEST_VALUE = "test value";

  // Non-loading versions:
  private final Map<Object, Object> map = new MapMaker().makeMap(); // Returns ConcurrentHashMap
  private final Cache<Object, Object> cache = CacheBuilder.newBuilder().recordStats().build();
  private final Cache<Object, Object> cacheNoStats = CacheBuilder.newBuilder().build();

      fail();
    } catch (IllegalStateException expected) {
    }
  }

  public void testReturnsPlainConcurrentHashMapWhenPossible() {
    Map<?, ?> map = new MapMaker().initialCapacity(5).makeMap();
    assertTrue(map instanceof ConcurrentHashMap);
  }

    MapMaker mapMaker = new MapMaker();
    // force MapMaker to use its own MapMakerInternalMap
    mapMaker.useCustomMap = true;
    testAddAndRemove(mapMaker.<String, AtomicInteger>makeMap());
  }

  private void testAddAndRemove(ConcurrentMap<String, AtomicInteger> map)
      throws ExecutionException, InterruptedException {

    MapMaker mapMaker = new MapMaker();
    // force MapMaker to use its own MapMakerInternalMap
    mapMaker.useCustomMap = true;
    testAddAndRemove(mapMaker.<String, AtomicInteger>makeMap());
  }

  private void testAddAndRemove(ConcurrentMap<String, AtomicInteger> map)
      throws ExecutionException, InterruptedException {

        new MapMaker().weakKeys().makeMap();

    /**
     * The map tracking lock nodes that can cause a lock acquisition cycle if acquired before this
     * node.
     */
    final Map<LockGraphNode, PotentialDeadlockException> disallowedPriorLocks =
        new MapMaker().weakKeys().makeMap();

    final String lockName;

    LockGraphNode(String lockName) {

      super(stripes);
      this.size = (mask == ALL_SET) ? Integer.MAX_VALUE : mask + 1;
      this.supplier = supplier;
      this.locks = new MapMaker().weakValues().makeMap();
    }

    @Override
    public L getAt(int index) {
      if (size != Integer.MAX_VALUE) {
        Preconditions.checkElementIndex(index, size());

    private final AtomicInteger counter = new AtomicInteger(0);
    private final ConcurrentMap<Object, Integer> uids =
        Platform.tryWeakKeys(new MapMaker()).makeMap();

    private Integer getUid(Object obj) {
      Integer uid = uids.get(obj);
      if (uid == null) {
        // One or more integer values could be skipped in the event of a race

    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
      in.defaultReadObject();
      MapMaker mapMaker = readMapMaker(in);
      delegate = mapMaker.makeMap();
      readEntries(in);
    }

    private Object readResolve() {
      return delegate;
    }
  }