.build();
    assertTrue(set.tailSet("california") instanceof ImmutableSortedSet);
    assertTrue(set.tailSet("fish") instanceof ImmutableSortedSet);
    assertThat(set.tailSet("fish")).containsExactly("over", "quick", "jumped").inOrder();
    assertThat(set.tailSet("a"))
        .containsExactly("a", "in", "the", "over", "quick", "jumped")
        .inOrder();
    assertTrue(set.tailSet("california").isEmpty());
  }

      for (List<Integer> contents : SAMPLE_INPUTS) {
        for (int i = 0; i < 10; i++) {
          assertEquals(
              filter((C) createUnfiltered(contents).tailSet(i), EVEN),
              filter(createUnfiltered(contents), EVEN).tailSet(i));
        }
      }
    }

    @SuppressWarnings("unchecked")
    public void testSubSet() {
      for (List<Integer> contents : SAMPLE_INPUTS) {

    @Override
    protected SortedSet<String> create(String[] elements) {
      List<String> list = Lists.newArrayList(elements);
      list.add("\0");
      return ImmutableSortedSet.copyOf(list).tailSet("\0\0");
    }
  }

  public static class ImmutableSortedSetSubsetGenerator extends TestStringSortedSetGenerator {
    @Override
    protected SortedSet<String> create(String[] elements) {

   *
   * <p>The {@link SortedSet#tailSet} documentation states that a subset of a subset throws an
   * {@link IllegalArgumentException} if passed a {@code fromElement} smaller than an earlier {@code
   * fromElement}. However, this method doesn't throw an exception in that situation, but instead
   * keeps the original {@code fromElement}.
   */
  @Override
  public ImmutableSortedSet<E> tailSet(E fromElement) {

      if (from == Bound.NO_BOUND && to == Bound.INCLUSIVE) {
        return set.headSet(lastInclusive, true);
      } else if (from == Bound.EXCLUSIVE && to == Bound.NO_BOUND) {
        return set.tailSet(firstExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.EXCLUSIVE) {
        return set.subSet(firstExclusive, false, lastExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.INCLUSIVE) {

   *
   * <p>The {@link SortedSet#tailSet} documentation states that a subset of a subset throws an
   * {@link IllegalArgumentException} if passed a {@code fromElement} smaller than an earlier {@code
   * fromElement}. However, this method doesn't throw an exception in that situation, but instead
   * keeps the original {@code fromElement}.
   */
  @Override
  public ImmutableSortedSet<E> tailSet(E fromElement) {

      if (from == Bound.NO_BOUND && to == Bound.INCLUSIVE) {
        return set.headSet(lastInclusive, true);
      } else if (from == Bound.EXCLUSIVE && to == Bound.NO_BOUND) {
        return set.tailSet(firstExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.EXCLUSIVE) {
        return set.subSet(firstExclusive, false, lastExclusive, false);
      } else if (from == Bound.EXCLUSIVE && to == Bound.INCLUSIVE) {

    }

    @Override
    public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
      synchronized (mutex) {
        return Synchronized.navigableSet(delegate().tailSet(fromElement, inclusive), mutex);
      }
    }

    @Override
    public SortedSet<E> tailSet(E fromElement) {
      return tailSet(fromElement, true);
    }

    }

    @Override
    public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
      synchronized (mutex) {
        return Synchronized.navigableSet(delegate().tailSet(fromElement, inclusive), mutex);
      }
    }

    @Override
    public SortedSet<E> tailSet(E fromElement) {
      return tailSet(fromElement, true);
    }

    @Override
    protected SortedSet<String> create(String[] elements) {
      List<String> list = Lists.newArrayList(elements);
      list.add("\0");
      return ImmutableSortedSet.copyOf(list).tailSet("\0\0");
    }
  }

  public static class ImmutableSortedSetSubsetGenerator extends TestStringSortedSetGenerator {
    @Override
    protected SortedSet<String> create(String[] elements) {