EJB - JPA Controller Not Work in EJB

Question

In the beginning, I created a EAR application by following the tutorial at http://wiki.netbeans.org/DevelopJavaEE6App/
After the application was completed successfully, as I wanted the Session Bean focusing business logic more, I utilized NetBeans wizard to create JPA Controller from Entities and moved all data manipulation methods from the Session Bean to the JPA Controller. As a result, it did not work.
CustomerJpaController:
package com.customerapp.jpa;
import com.customerapp.entity.Customer;
import com.customerapp.jpa.exceptions.NonexistentEntityException;
import com.customerapp.jpa.exceptions.PreexistingEntityException;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
import javax.persistence.EntityNotFoundException;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Root;
import com.customerapp.entity.DiscountCode;
public class CustomerJpaController {
    public CustomerJpaController() {
        emf = Persistence.createEntityManagerFactory("CustomerApp-ejbPU");
    private EntityManagerFactory emf = null;
    public EntityManager getEntityManager() {
        return emf.createEntityManager();
    public void create(Customer customer) throws PreexistingEntityException, Exception {
        EntityManager em = null;
        try {
            em = getEntityManager();
            em.getTransaction().begin();
            DiscountCode discountCode = customer.getDiscountCode();
            if (discountCode != null) {
                discountCode = em.getReference(discountCode.getClass(), discountCode.getDiscountCode());
                customer.setDiscountCode(discountCode);
            em.persist(customer);
            if (discountCode != null) {
                discountCode.getCustomerList().add(customer);
                discountCode = em.merge(discountCode);
            em.getTransaction().commit();
        } catch (Exception ex) {
            if (findCustomer(customer.getCustomerId()) != null) {
                throw new PreexistingEntityException("Customer " + customer + " already exists.", ex);
            throw ex;
        } finally {
            if (em != null) {
                em.close();
    public void edit(Customer customer) throws NonexistentEntityException, Exception {
        EntityManager em = null;
        try {
            em = getEntityManager();
            em.getTransaction().begin();
            Customer persistentCustomer = em.find(Customer.class, customer.getCustomerId());
            DiscountCode discountCodeOld = persistentCustomer.getDiscountCode();
            DiscountCode discountCodeNew = customer.getDiscountCode();
            if (discountCodeNew != null) {
                discountCodeNew = em.getReference(discountCodeNew.getClass(), discountCodeNew.getDiscountCode());
                customer.setDiscountCode(discountCodeNew);
            customer = em.merge(customer);
            if (discountCodeOld != null && !discountCodeOld.equals(discountCodeNew)) {
                discountCodeOld.getCustomerList().remove(customer);
                discountCodeOld = em.merge(discountCodeOld);
            if (discountCodeNew != null && !discountCodeNew.equals(discountCodeOld)) {
                discountCodeNew.getCustomerList().add(customer);
                discountCodeNew = em.merge(discountCodeNew);
            em.getTransaction().commit();
        } catch (Exception ex) {
            String msg = ex.getLocalizedMessage();
            if (msg == null || msg.length() == 0) {
                Integer id = customer.getCustomerId();
                if (findCustomer(id) == null) {
                    throw new NonexistentEntityException("The customer with id " + id + " no longer exists.");
            throw ex;
        } finally {
            if (em != null) {
                em.close();
    public void destroy(Integer id) throws NonexistentEntityException {
        EntityManager em = null;
        try {
            em = getEntityManager();
            em.getTransaction().begin();
            Customer customer;
            try {
                customer = em.getReference(Customer.class, id);
                customer.getCustomerId();
            } catch (EntityNotFoundException enfe) {
                throw new NonexistentEntityException("The customer with id " + id + " no longer exists.", enfe);
            DiscountCode discountCode = customer.getDiscountCode();
            if (discountCode != null) {
                discountCode.getCustomerList().remove(customer);
                discountCode = em.merge(discountCode);
            em.remove(customer);
            em.getTransaction().commit();
        } finally {
            if (em != null) {
                em.close();
    public List<Customer> findCustomerEntities() {
        return findCustomerEntities(true, -1, -1);
    public List<Customer> findCustomerEntities(int maxResults, int firstResult) {
        return findCustomerEntities(false, maxResults, firstResult);
    private List<Customer> findCustomerEntities(boolean all, int maxResults, int firstResult) {
        EntityManager em = getEntityManager();
        try {
            CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
            cq.select(cq.from(Customer.class));
            Query q = em.createQuery(cq);
            if (!all) {
                q.setMaxResults(maxResults);
                q.setFirstResult(firstResult);
            return q.getResultList();
        } finally {
            em.close();
    public Customer findCustomer(Integer id) {
        EntityManager em = getEntityManager();
        try {
            return em.find(Customer.class, id);
        } finally {
            em.close();
    public int getCustomerCount() {
        EntityManager em = getEntityManager();
        try {
            CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
            Root<Customer> rt = cq.from(Customer.class);
            cq.select(em.getCriteriaBuilder().count(rt));
            Query q = em.createQuery(cq);
            return ((Long) q.getSingleResult()).intValue();
        } finally {
            em.close();
}How can I integrate my EJB with my JPA controller? Please help

Answer 1

CustomerSessionBean:
package com.customerapp.ejb;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.annotation.Resource;
import javax.ejb.Stateless;
import javax.ejb.LocalBean;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import java.util.List;
import com.customerapp.entity.Customer;
import com.customerapp.entity.DiscountCode;
import com.customerapp.jpa.CustomerJpaController;
import com.customerapp.jpa.DiscountCodeJpaController;
@Stateless
@LocalBean
public class CustomerSessionBean {
    @Resource(name = "jms/NotificationQueue")
    private Queue notificationQueue;
    @Resource(name = "jms/NotificationQueueFactory")
    private ConnectionFactory notificationQueueFactory;
    CustomerJpaController customerJpa;
    DiscountCodeJpaController discountCodeJpa;
    @PostConstruct
    public void initJpa(){
        customerJpa = new CustomerJpaController();
        discountCodeJpa = new DiscountCodeJpaController();
    @PreDestroy
    public void removeJpa() {
        customerJpa = null;
        discountCodeJpa = null;
    public void create(Customer customer) {
        try {
            customerJpa.create(customer);
        } catch (Exception ex) {
            Logger.getLogger(CustomerSessionBean.class.getName()).log(Level.SEVERE, null, ex);
    public List<Customer> retrieve() {       
        return customerJpa.findCustomerEntities();
    public Customer update(Customer customer) {
        Customer updatedCustomer;
        try {
            Integer customerId = customer.getCustomerId();
            customerJpa.edit(customer);
            updatedCustomer = customerJpa.findCustomer(customerId);
            sendJMSMessageToNotificationQueue(updatedCustomer);
            System.out.println("Customer updated in CustomerSessionBean!");
            return updatedCustomer;
        } catch (JMSException ex) {
            Logger.getLogger(CustomerSessionBean.class.getName()).log(Level.SEVERE, null, ex);
        } catch (Exception ex) {
            Logger.getLogger(CustomerSessionBean.class.getName()).log(Level.SEVERE, null, ex);
        return customer;
    public List<DiscountCode> getDiscountCodes() {
        return discountCodeJpa.findDiscountCodeEntities();
    private Message createJMSMessageForjmsNotificationQueue(Session session, Object messageData) throws JMSException {
        TextMessage tm = session.createTextMessage();
        tm.setText(messageData.toString());
        return tm;
    private void sendJMSMessageToNotificationQueue(Object messageData) throws JMSException {
        Connection connection = null;
        Session session = null;
        try {
            connection = notificationQueueFactory.createConnection();
            session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            MessageProducer messageProducer = session.createProducer(notificationQueue);
            messageProducer.send(createJMSMessageForjmsNotificationQueue(session, messageData));
        } finally {
            if (session != null) {
                try {
                    session.close();
                } catch (JMSException e) {
                    Logger.getLogger(this.getClass().getName()).log(Level.WARNING, "Cannot close session", e);
            if (connection != null) {
                connection.close();
}ERROR:
Caused by: java.lang.IllegalArgumentException: The type [null] is not the expected [EntityType] for the key class [class com.customerapp.entity.Customer].
        at org.eclipse.persistence.internal.jpa.metamodel.MetamodelImpl.entity(MetamodelImpl.java:152)
        at org.eclipse.persistence.internal.jpa.querydef.AbstractQueryImpl.from(AbstractQueryImpl.java:97)
        at com.customerapp.jpa.CustomerJpaController.findCustomerEntities(CustomerJpaController.java:140)
        at com.customerapp.jpa.CustomerJpaController.findCustomerEntities(CustomerJpaController.java:129)
        at com.customerapp.ejb.CustomerSessionBean.retrieve(CustomerSessionBean.java:64)