code: @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ResponseBody
    public ValidationResultInterface processValidationError(
        final MethodArgumentNotValidException pexception) {
      final BindingResult result = pexception.getBindingResult();
      final List<FieldError> fieldErrors = result.getFieldErrors();
  
      return processFieldErrors(fieldErrors);
    }
docs: handle validation errors.
  
  @param pexception exception which is thrown when data is invalid.
  @return ValidationResultData with validation errors