Whi if i close a EntityMaanger into a java SE app i not can get a new EntityManager fro ma apposite method?

Hi all .
It is the first time that i write on mailing list of OPEJPA .
I am movice to OpenJPA and i have a question.
I have writed a java SE app simple.
I have created a class Gestore.java .

my DAO is :

package gestoreentita;

import eentita.Persona;
import java.util.List;
import java.util.logging.Logger;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

/**

* @author utente_javaee7
*/
public class Gestore {

private static final Logger log =
Logger.getLogger(Gestore.class.getName());
EntityManagerFactory emf = null;
EntityManager em = null;

public Gestore() {
this.emf =
Persistence.createEntityManagerFactory("prova1openjpaallPU");

log.info("created the EntyManagerFactory " + emf.toString());

public EntityManager getEntityManager() {

if (this.em == null) {
em = emf.createEntityManager();
log.info("created the EntyManager " + em.toString());

return this.em;

public void closeEntytyManager() {
if (em.isOpen()) {
em.close();
em = null;
log.info("closed the EntyManager " + em.toString());

public void closeEntytyManagerFactory() {
if (emf.isOpen()) {
log.info("now i close the EntyManagerFactory " +
emf.toString());
emf.close();
log.info("the EntyManagerFactory now is :" + emf.toString());

public Persona savePersona(Persona newdetachedPerson) {

try {
em = this.getEntityManager();
em.getTransaction().begin();

em.persist(newdetachedPerson);
em.getTransaction().commit();
log.info("Persona è stata salvata in database con id =" +
newdetachedPerson.getId());
} catch (Exception e) {
em.getTransaction().rollback();
log.info("error into operation of persistence... Person not
saved!!!!");

} finally {
this.closetransaction();

this.closeEntytyManager();

return newdetachedPerson;

public List<Persona> getListPersona() {
List<Persona> lista = null;
try {
em = this.getEntityManager();

log.info("Creatop EntytyManager =" + em.toString());
log.info("Tentativo di ritrovare le enttita persona nel
database:");

lista = em.createQuery("select p from Persona
p").getResultList();

log.info("------ritrovate :" + lista.size());

} catch (Exception e) {
log.info("i have a Exception :" + e.getLocalizedMessage());
} finally {
this.closeEntytyManager();

return lista;

public void closetransaction() {
if (em.getTransaction().isActive()) {
em.close();
log.info("transaction closed!!!");

my application with class Main is:

package mauro.application;

import eentita.Persona;
import gestoreentita.Gestore;
import java.awt.HeadlessException;
import java.util.List;
import java.util.logging.Logger;
import javax.swing.JOptionPane;

/**

* @author utente_javaee7
*/
public class Main {

private static final Logger LOG =
Logger.getLogger(Main.class.getName());

public static Logger getLOG() {
return LOG;

private Gestore gestore;

public void closeEntityManagerFactory() {
this.gestore.closeEntytyManagerFactory();

public Main() {
this.gestore = new Gestore();

public static void main(String[] arg) {
Main main = new Main();
main.test1();

public void test1() {
try {
Persona p1, p2, p3, p4;
p1 = new Persona();
p1.setNome("pippo");

p2 = new Persona();
p2.setNome("pluto");
p3 = new Persona();
p3.setNome("paperino");
p4 = new Persona();
p4.setNome("archimede");

p1 = gestore.savePersona(p1);
JOptionPane.showMessageDialog(null, "Salvato: " + p1.getNome()
+ " con ID= : " + p1.getId());

p2 = gestore.savePersona(p2);
JOptionPane.showMessageDialog(null, "Salvato: " + p2.getNome()
+ " con ID= : " + p2.getId());

p3 = gestore.savePersona(p3);
JOptionPane.showMessageDialog(null, "Salvato: " + p3.getNome()
+ " con ID= : " + p3.getId());

p4 = gestore.savePersona(p4);
JOptionPane.showMessageDialog(null, "Salvato: " + p4.getNome()
+ " con ID= : " + p4.getId());

List<Persona> listaPersone = gestore.getListPersona();
JOptionPane.showMessageDialog(null, "into the db are present :
" + listaPersone.size() + " Persone");

} catch (Exception e) {
LOG.info("i have a exception: " + e.getLocalizedMessage());
} catch (Throwable t) {
LOG.info("i have a error: " + t.getLocalizedMessage());
} finally {
this.gestore.closeEntytyManagerFactory();

public Gestore getGestore() {
return gestore;