* contention. See above for explanation. This method suffers the usual non-modularity problems of
   * optimistic retry code, relying on rechecked sets of reads.
   *
   * @param x the value
   * @param hc the hash code holder
   * @param wasUncontended false if CAS failed before call
   */
  final void retryUpdate(long x, @CheckForNull int[] hc, boolean wasUncontended) {
    int h;
    if (hc == null) {

  }

  @J2ktIncompatible // Kotlin Native's regex is based on Apache Harmony, like old Android
  @GwtIncompatible // java.util.regex.Pattern
  @AndroidIncompatible // Bug in older versions of Android we test against, since fixed.
  public void testPatternSplitLookBehind() {
    if (!CommonPattern.isPcreLike()) {
      return;
    }
    String toSplit = ":foo::barbaz:";

    return (nullableReference == null) ? Optional.<T>absent() : new Present<T>(nullableReference);
  }

  Optional() {}

  /**
   * Returns {@code true} if this holder contains a (non-null) instance.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> no differences.
   */
  public abstract boolean isPresent();

  /**

 * {@link #writeTo} and {@link #readFrom} methods. Both serialized forms will continue to be
 * supported by future versions of this library. However, serial forms generated by newer versions
 * of the code may not be readable by older versions of the code (e.g., a serialized Bloom filter
 * generated today may <i>not</i> be readable by a binary that was compiled 6 months ago).
 *

   *
   * @param loader the cache loader used to obtain new values
   * @return a cache having the requested features
   */
  public <K1 extends K, V1 extends V> LoadingCache<K1, V1> build(
      CacheLoader<? super K1, V1> loader) {
    checkWeightWithWeigher();
    return new LocalCache.LocalLoadingCache<>(this, loader);
  }

  /**

     * Closeable}. (For more about the flavors, see <a
     * href="https://github.com/google/guava#adding-guava-to-your-build">Adding Guava to your
     * build</a>.)
     *
     * <p>Be careful when targeting an older SDK than you are building against (most commonly when
     * building for Android): Ensure that any object you pass implements the interface not just in

    }

    private static final long serialVersionUID = 5;
  }

  public void testMutableValues() {
    IntHolder holderA = new IntHolder(1);
    IntHolder holderB = new IntHolder(2);
    Map<String, IntHolder> map = ImmutableSortedMap.of("a", holderA, "b", holderB);
    holderA.value = 3;
    assertTrue(map.entrySet().contains(Maps.immutableEntry("a", new IntHolder(3))));

  }

  public void testGetAndAdd() {
    Count holder = new Count(20);
    assertEquals(20, holder.get());
    holder.add(1);
    assertEquals(21, holder.get());
  }

  public void testAddAndGet() {
    Count holder = new Count(20);
    assertEquals(21, holder.addAndGet(1));
  }

  public void testGetAndSet() {
    Count holder = new Count(10);
    assertEquals(10, holder.getAndSet(20));
    assertEquals(20, holder.get());

    ImmutableMultimap.Builder<String, Integer> builder = new Builder<>();
    final StringHolder holder = new StringHolder();
    holder.string = "one";
    Entry<String, Integer> entry =
        new AbstractMapEntry<String, Integer>() {
          @Override
          public String getKey() {
            return holder.string;
          }

          @Override
          public Integer getValue() {
            return 1;

                      holder.count++;
                      return null;
                    }
                  },
                  directExecutor());
        }
      }
      settableFuture.set(null);
      completeLengthChecks = allAsList(lengthChecks).get();
    } finally {
      service.shutdown();
    }
    assertThat(holder.count).isEqualTo(ITERATION_COUNT);