Netbeans JSF!!!!

public DataModel getTbcompanys() {
EntityManager em = getEntityManager();
try{
Query q = em.createQuery("select object(o) from Tbcompany as o ORDER BY o.id");
q.setMaxResults(batchSize);
q.setFirstResult(firstItem);
model = new ListDataModel(q.getResultList());
return model;
} finally {
em.close();
}
}

trong file Controller