Problem solved.. i have used method update of session
public static void changeOccup(String email,String occup){Session sess=null;try{sess=UtilClass.createSession();Transaction tr=sess.beginTransaction();Userrecord u=(Userrecord) sess.get(Userrecord.class, email); u.setOccupation(occup); sess.update(u);tr.commit();}catch(Exception e){} }