Costume validation for before Update(PUT)

hi cuba team ,i have one costume validation for before update entity listener .when i run the cuba update REST API in postman it show “data error” but i want to costume exception . bellow i mention the code.

      public class ProfileDetailsEntityListener implements BeforeUpdateEntityListener<ProfileDetails> {

      private Logger log = LoggerFactory.getLogger(UserDetailsServiceBean.class);

         public void onBeforeUpdate (ProfileDetails entity, EntityManager entityManager) {

         	Query query = entityManager.createQuery("select u from matrimony$ProfileDetails u where  u.profileMobileNo = :mobile and id: != currentID");
      	query.setParameter("mobile", entity.getProfileMobileNo());
         	query.setParameter("currentID", entity.getId());
             List<?> count =  query.getResultList();
         	if (count.size() > 0) {
            		log.warn("------->Service call error: A user with the same email/mobile already exists : "	+ entity.getProfileMobileNo());
          		throw new ValidationException("The mobile Number is already registerd!");
      **`Preformatted text`	}}

i want to print my costume validation error message.

Maybe this post can help you.