### Question:
Types { public static WildcardType subtypeOf(Type bound) { Type[] upperBounds; if (bound instanceof WildcardType) { upperBounds = ((WildcardType) bound).getUpperBounds(); } else { upperBounds = new Type[] {bound}; } return new WildcardTypeImpl(upperBounds, EMPTY_TYPE_ARRAY); } private  Types(); static String generatedJsonAdapterName(Class<?> clazz); static String generatedJsonAdapterName(String className); static @Nullable Set<? extends Annotation> nextAnnotations(
      Set<? extends Annotation> annotations, Class<? extends Annotation> jsonQualifier); static ParameterizedType newParameterizedType(Type rawType, Type... typeArguments); static ParameterizedType newParameterizedTypeWithOwner(
      Type ownerType, Type rawType, Type... typeArguments); static GenericArrayType arrayOf(Type componentType); static WildcardType subtypeOf(Type bound); static WildcardType supertypeOf(Type bound); static Class<?> getRawType(Type type); static Type collectionElementType(Type context, Class<?> contextRawType); static boolean equals(@Nullable Type a, @Nullable Type b); static Set<? extends Annotation> getFieldJsonQualifierAnnotations(
      Class<?> clazz, String fieldName);  }### Answer:
@Test public void subtypeOf() throws Exception { Type listOfWildcardType = TypesTest.class.getDeclaredField("listSubtype").getGenericType(); Type expected = Types.collectionElementType(listOfWildcardType, List.class); assertThat(Types.subtypeOf(CharSequence.class)).isEqualTo(expected); }