public static ParameterizedType mapOf(Type keyType, Type valueType) {
    return parameterizedType(Map.class, keyType, valueType);
  }
@Test
  public void createMapType() {
    ParameterizedType type = Types.mapOf(String.class, Person.class);
    assertThat(type.getRawType()).isEqualTo(Map.class);
    assertThat(type.getActualTypeArguments()).isEqualTo(new Type[] {String.class, Person.class});
  }