return Arrays.asList(type.getInterfaces());
          }

          @Override
          @Nullable Class<?> getSuperclass(Class<?> type) {
            return type.getSuperclass();
          }
        };

    /** For just classes, we don't have to traverse interfaces. */
    final TypeCollector<K> classesOnly() {

  public void testGetGenericSuperclass_withSuperclass() {
    TypeToken<? super ArrayList<String>> superToken =
        new TypeToken<ArrayList<String>>() {}.getGenericSuperclass();
    assertEquals(ArrayList.class.getSuperclass(), superToken.getRawType());
    assertEquals(
        String.class, ((ParameterizedType) superToken.getType()).getActualTypeArguments()[0]);

  public void testGetGenericSuperclass_withSuperclass() {
    TypeToken<? super ArrayList<String>> superToken =
        new TypeToken<ArrayList<String>>() {}.getGenericSuperclass();
    assertEquals(ArrayList.class.getSuperclass(), superToken.getRawType());
    assertEquals(
        String.class, ((ParameterizedType) superToken.getType()).getActualTypeArguments()[0]);