Validação Request Param

Method in controller:
@RequestMapping("/hi")
public String sayHi(@Size(max = 10, message = "name should at most 10 characters long") @RequestParam("name") String name) {
    return "Hi " + name;

Controller Advice:
@ExceptionHandler(value = {ConstraintViolationException.class})
@ResponseStatus(value = HttpStatus.BAD_REQUEST)
public String handleValidationFailure(ConstraintViolationException ex) {

  StringBuilder messages = new StringBuilder();

  for (ConstraintViolation<?> violation : ex.getConstraintViolations()) {
      messages.append(violation.getMessage() + "\n");
  }

  return messages.toString();
}

Config:
@Bean
public MethodValidationPostProcessor methodValidationPostProcessor() {
  return new MethodValidationPostProcessor();
}