private interface TypeB {}

  private static class HasBoth extends TypeA implements TypeB {}

  @GwtIncompatible // Iterables.filter(Iterable, Class)
  public void testFilterByType_iterator() throws Exception {
    HasBoth hasBoth = new HasBoth();
    Iterable<TypeA> alist = Lists.newArrayList(new TypeA(), new TypeA(), hasBoth, new TypeA());
    Iterable<TypeB> blist = filter(alist, TypeB.class);

  private interface TypeB {}

  private static class HasBoth extends TypeA implements TypeB {}

  @GwtIncompatible // Iterables.filter(Iterable, Class)
  public void testFilterByType() throws Exception {
    HasBoth hasBoth = new HasBoth();
    FluentIterable<TypeA> alist =
        FluentIterable.from(asList(new TypeA(), new TypeA(), hasBoth, new TypeA()));
    Iterable<TypeB> blist = alist.filter(TypeB.class);