问PostgreSQL不使用JPA、JEE6关闭事务

EN

public Integer ogetNumber() {


        EntityManager em = emf.createEntityManager();

        Object obj = null;


        try {
            Query qry = em.createQuery("SELECT MAX(p.number) FROM Number p");
            obj = qry.getSingleResult();
            if (obj == null) {
                return 0;
            }
            return (Integer) obj;
        } catch (Exception e) {
            System.out.printf(e.getMessage());
        } finally {
             if (em != null) {
                em.close();
            }



        }
         return (Integer) obj;
    }

<?xml version="1.0" encoding="UTF-8"?> <persistence version="1.0"
    xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">  
<persistence-unit name="PersistenceUnit" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <class>entities.Validacion</class>
    <class>entities.ValidacionDB</class>

    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
      <property name="hibernate.show_sql" value="false"/>
      <property name="hibernate.connection.username" value="postgres"/>
      <property name="hibernate.connection.driver_class" value="org.postgresql.Driver"/>
      <property name="hibernate.connection.password" value="password"/>
      <property name="hibernate.connection.url" value="jdbc:postgresql://localhost:5432/test"/>
      <property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider"/>
      <property name="hibernate.hbm2ddl.auto" value="update"/>
    </properties>
</persistence-unit>