code: private static boolean isPropertyType(Class<?> type) {
          return type.isPrimitive() ||
                  type == String.class ||
                  type == Date.class ||
                  type == Calendar.class ||
                  ClassUtils.wrapperToPrimitive(type) != null;
      }
docs: Whether a property cannot be represented by a resource but must stem
  from a value map representing the properties of a resource.