@Override public void validate(Object obj, Errors errors) { Pet pet = (Pet) obj; String name = pet.getName(); // name validation if (!StringUtils.hasLength(name)) { errors.rejectValue("name", REQUIRED, REQUIRED); } // type validation if (pet.isNew() && pet.getType() == null) { errors.rejectValue("type", REQUIRED, REQUIRED); } // birth date validation if (pet.getBirthDate() == null) { errors.rejectValue("birthDate", REQUIRED, REQUIRED); } }