code: private boolean isAllowed(Field field) {
          return ClassUtils.isPrimitiveOrWrapper(field.getType())
                  || CharSequence.class.isAssignableFrom(field.getType())
                  || List.class.isAssignableFrom(field.getType());
      }
docs: Verifies if the given field follow the rules.
  
  @param field Field to be verified
  @return True if field is allowed and false otherwise.