() -> CacheBuilder.newBuilder().maximumSize(1).weigher(constantWeigher(42)));
  }

  @GwtIncompatible // weakKeys
  public void testKeyStrengthSetTwice() {
    CacheBuilder<Object, Object> builder1 = CacheBuilder.newBuilder().weakKeys();
    assertThrows(IllegalStateException.class, () -> builder1.weakKeys());
  }

  @GwtIncompatible // weakValues
  public void testValueStrengthSetTwice() {

        () -> CacheBuilder.newBuilder().maximumSize(1).weigher(constantWeigher(42)));
  }

  @GwtIncompatible // weakKeys
  public void testKeyStrengthSetTwice() {
    CacheBuilder<Object, Object> builder1 = CacheBuilder.newBuilder().weakKeys();
    assertThrows(IllegalStateException.class, () -> builder1.weakKeys());
  }

  @GwtIncompatible // weakValues
  public void testValueStrengthSetTwice() {

  private static Iterable<MapMaker> allWeakKeyStrengthMakers() {
    return ImmutableList.of(createMapMaker().weakKeys(), createMapMaker().weakKeys().weakValues());
  }

  private static Iterable<MapMaker> allWeakValueStrengthMakers() {
    return ImmutableList.of(
        createMapMaker().weakValues(), createMapMaker().weakKeys().weakValues());
  }

  public void testNullParameters() throws Exception {

  private static Iterable<MapMaker> allWeakKeyStrengthMakers() {
    return ImmutableList.of(createMapMaker().weakKeys(), createMapMaker().weakKeys().weakValues());
  }

  private static Iterable<MapMaker> allWeakValueStrengthMakers() {
    return ImmutableList.of(
        createMapMaker().weakValues(), createMapMaker().weakKeys().weakValues());
  }

  public void testNullParameters() throws Exception {

   * that reclamation becomes important.
   */
  @J2ktIncompatible
  static MapMaker tryWeakKeys(MapMaker mapMaker) {
    return mapMaker.weakKeys();
  }

  static <E extends Enum<E>> Class<E> getDeclaringClassOrObjectForJ2cl(E e) {
    return e.getDeclaringClass();
  }

  static int reduceIterationsIfGwt(int iterations) {
    return iterations;

   * that reclamation becomes important.
   */
  @J2ktIncompatible
  static MapMaker tryWeakKeys(MapMaker mapMaker) {
    return mapMaker.weakKeys();
  }

  static <E extends Enum<E>> Class<E> getDeclaringClassOrObjectForJ2cl(E e) {
    return e.getDeclaringClass();
  }

  static int reduceIterationsIfGwt(int iterations) {
    return iterations;

       * UnsignedBytesBenchmark. TODO(cpovirk): benchmark this
       */
      /*
       * A CopyOnWriteArraySet<WeakReference> is faster than a newSetFromMap of a MapMaker map with
       * weakKeys() and concurrencyLevel(1), even up to at least 12 cached exception types.
       */
      private static final Set<WeakReference<Class<? extends Exception>>> validClasses =
          new CopyOnWriteArraySet<>();

       * UnsignedBytesBenchmark. TODO(cpovirk): benchmark this
       */
      /*
       * A CopyOnWriteArraySet<WeakReference> is faster than a newSetFromMap of a MapMaker map with
       * weakKeys() and concurrencyLevel(1), even up to at least 12 cached exception types.
       */
      private static final Set<WeakReference<Class<? extends Exception>>> validClasses =
          new CopyOnWriteArraySet<>();

    final Map<LockGraphNode, ExampleStackTrace> allowedPriorLocks =
        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) {

    CountingLoader countingLoader = new CountingLoader();
    LoadingCache<Object, Object> cache =
        CacheBuilder.newBuilder().concurrencyLevel(1).weakKeys().build(countingLoader);

    Object key = new Object();
    assertNotNull(cache.getUnchecked(key));
    assertEquals(1, cache.size());

    CacheTesting.simulateKeyReclamation(cache, key);