Criando um persistence unit na mão !

A Configuração :

 Ejb3Configuration ejbconf = new Ejb3Configuration();  
   ejbconf.setProperty("hibernate.connection.datasource", "java:/" + datasourceName);  
   ejbconf.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLInnoDBDialect");  
   ejbconf.setProperty("hibernate.show_sql", "false");  
   ejbconf.setProperty("hibernate.ejb.naming_strategy","com.fcl.greenfield.naming.FCLNamingStrategy");  
   ejbconf.setProperty("hibernate.hbm2ddl.auto", "update");  

Usando :

 Logger.info("Building SessionFactory");
    EntityManagerFactory emf = ejbconf.createEntityManagerFactory();
    EntityManager em = emf.createEntityManager(); 

Facil né ? ! aeuUAEhuaehuaheuHEuae

Sem mais !