EJB3 persistence in a Tomcat webapp (ThreadLocal pattern)

Question

When you only want to use EJB3 persistence, and not the whole EJB3 stack).
First posted to http://forum.hibernate.org/viewtopic.php?t=963478 without an answer!
In the document "Using Hibernate with Tomcat" (http://www.hibernate.org/114.html), it is suggested that you create a ServletContextListener - like the one below - where the listener initializes and closes Hibernate on deployment and undeployment of your webapp.
public class HibernateListener implements ServletContextListener {
    public void contextInitialized(ServletContextEvent event) {
        HibernateUtil.getSessionFactory(); // Just call the static initializer of that class  
    public void contextDestroyed(ServletContextEvent event) {
        HibernateUtil.getSessionFactory().close(); // Free all resources
}My question is: If I want to use Hibernate as an EJB3 persistence engine in a Webapp running in Tomcat, do I make a similar ServletContextListener like this:
public class EntityManagerListener implements ServletContextListener {
    public void contextInitialized(ServletContextEvent event) {
        EntityManagerUtil.getEntityManagerFactory(); // Just call the static initializer of that class  
    public void contextDestroyed(ServletContextEvent event) {
        EntityManagerUtil.getEntityManagerFactory().close(); // Free all resources
public class EntityManagerUtil {
    private static EntityManagerFactory emf;
    public static final ThreadLocal<EntityManager> entitymanager = new ThreadLocal<EntityManager>();
    public static EntityManagerFactory getEntityManagerFactory() {
        if (emf == null) {
            // Create the EntityManagerFactory
            emf = Persistence.createEntityManagerFactory("example");
        return emf;
    public static EntityManager getEntityManager() {
        EntityManager em = entitymanager.get();
        // Create a new EntityManager
        if (em == null) {
            em = emf.createEntityManager();
            entitymanager.set(em);
        return em;
    public static void closeEntityManager() {
        EntityManager em = entitymanager.get();
        entitymanager.set(null);
        if (em != null) em.close();
}And then in my webapp use the following code:
public Person findByName(String name) {
    EntityManager em = EntityManagerUtil.getEntityManager();
    Query q = em.createQuery("select person from Person as person where name=:param");
    q.setParameter("param", name);
    Person p = (Person) q.getSingleResult();
    em.close();
    return p;
}Would that be the right way to do it?

Answer 1

Sun's reference JPA implementation (= EJB3 persistence) can be obtained from
https://glassfish.dev.java.net/downloads/persistence/JavaPersistence.html