try {
      cache.getUnchecked("bar");
      fail();
    } catch (UncheckedExecutionException expected) {
    }
    assertEquals(2, callCount.get());
  }

  /**
   * Test-helper method that performs {@code nThreads} concurrent calls to {@code cache.get(key)} or
   * {@code cache.getUnchecked(key)}, and returns a List containing each of the results. The result

  private static final long SPIN_THRESHOLD_NANOS = 1000L;

  private static final AtomicHelper ATOMIC_HELPER;

  static {
    AtomicHelper helper;
    Throwable thrownUnsafeFailure = null;
    Throwable thrownAtomicReferenceFieldUpdaterFailure = null;

    try {
      helper = new UnsafeAtomicHelper();
    } catch (Exception | Error unsafeFailure) { // sneaky checked exception

    try {
      cache.getUnchecked("bar");
      fail();
    } catch (UncheckedExecutionException expected) {
    }
    assertEquals(2, callCount.get());
  }

  /**
   * Test-helper method that performs {@code nThreads} concurrent calls to {@code cache.get(key)} or
   * {@code cache.getUnchecked(key)}, and returns a List containing each of the results. The result

    static final class Helper<K, V>
        implements InternalEntryHelper<
            K, V, StrongKeyStrongValueEntry<K, V>, StrongKeyStrongValueSegment<K, V>> {
      private static final Helper<?, ?> INSTANCE = new Helper<>();

      @SuppressWarnings("unchecked")
      static <K, V> Helper<K, V> instance() {
        return (Helper<K, V>) INSTANCE;
      }

      @Override

  }

  /**
   * Determines whether a BMP character is upper case according to {@linkplain
   * Character#isUpperCase(char) Java's definition}.
   *
   * @deprecated Some uppercase characters are supplementary characters; see the class
   *     documentation.
   * @since 19.0 (since 1.0 as constant {@code JAVA_UPPER_CASE})
   */
  @Deprecated
  public static CharMatcher javaUpperCase() {

   * declared by interface {@code Iterable}.
   *
   * <p>If this type is a type variable or wildcard, its upper bounds are examined and those that
   * are either an interface or upper-bounded only by interfaces are returned. This means that the
   * returned types could include type variables too.
   */
  final ImmutableList<TypeToken<? super T>> getGenericInterfaces() {

  }

  /**
   * Determines whether a BMP character is upper case according to {@linkplain
   * Character#isUpperCase(char) Java's definition}.
   *
   * @deprecated Some uppercase characters are supplementary characters; see the class
   *     documentation.
   * @since 19.0 (since 1.0 as constant {@code JAVA_UPPER_CASE})
   */
  @Deprecated
  public static CharMatcher javaUpperCase() {

      Iterable<? extends ListenableFuture<? extends V>> futures) {
    return new FutureCombiner<>(true, ImmutableList.copyOf(futures));
  }

  /**
   * A helper to create a new {@code ListenableFuture} whose result is generated from a combination
   * of input futures.
   *
   * <p>See {@link #whenAllComplete} and {@link #whenAllSucceed} for how to instantiate this class.
   *