EJB / EE :: Bean Validation Error In JPA When Trying To Persist Entity

i get this error when trying to Persist a customer Entity in my web application using netbeans with the default glassfish server persistence provider eclipselink(JPA2.0)

error is

SEVERE: javax.validation.ConstraintViolationException: Bean Validation constraint(s) violated while executing Automatic Bean Validation on callback event:'prePersist'. Please refer to embedded ConstraintViolations for details.

the table that i want to write to has the following colums
id ==> primarykey auto increment not null int
name == varchar(45) not null
phone ==> varchar(19)
nationalIdNo ==>varchar(19)
balance ==> bigdecimal(6,2) not null default(0.00)

in my addNewCustomer i only need to set name, phone and nationalIdNo only this is my code

/*
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package session;

import cart.Cart;
import entity.Customer;
import javax.ejb.Stateless;
import javax.ejb.LocalBean;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

[code].....

why am i getting this error? and how do you do a bean validation?