@Partially.GwtIncompatible("AVAILABLE but requires exceptionType to be Throwable.class")
  public static <V extends @Nullable Object, X extends Throwable> ListenableFuture<V> catching(
      ListenableFuture<? extends V> input,
      Class<X> exceptionType,
      Function<? super X, ? extends V> fallback,
      Executor executor) {
    return AbstractCatchingFuture.create(input, exceptionType, fallback, executor);
  }

  /**

      Class<X> exceptionType, ClosingFunction<? super X, ? extends V> fallback, Executor executor) {
    return catchingMoreGeneric(exceptionType, fallback, executor);
  }

  // Avoids generic type capture inconsistency problems where |? extends V| is incompatible with V.
  private <X extends Throwable, W extends V> ClosingFuture<V> catchingMoreGeneric(