assertFalse(collection.spliterator().hasCharacteristics(Spliterator.NONNULL));
    }
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSpliteratorNotImmutable_CollectionAllowsAdd() {
    // If add is supported, verify that IMMUTABLE is not reported.
    synchronized (collection) { // for Collections.synchronized
      assertFalse(collection.spliterator().hasCharacteristics(Spliterator.IMMUTABLE));
    }
  }

      return spliterator.getComparator();
    }

    final long getExactSizeIfKnown() {
      return spliterator.getExactSizeIfKnown();
    }

    final boolean hasCharacteristics(int characteristics) {
      return spliterator.hasCharacteristics(characteristics);
    }
  }

  private static final class GeneralSpliteratorOfObject<E extends @Nullable Object>
      extends GeneralSpliterator<E> {

            | Spliterator.SUBSIZED
            | extraCharacteristics;
      }

      @Override
      @CheckForNull
      public Comparator<? super T> getComparator() {
        if (hasCharacteristics(Spliterator.SORTED)) {
          return comparator;
        } else {
          throw new IllegalStateException();
        }
      }
    }