Error using Resource Local Entity Manager

[Steven Lennon]

Hi All,

I am study for the SCBCD exam and trying out different scenerios with JTA and Resource Local Managed Entity Managers. I came across this scenerio which I can't explain what is happening. I am receiving the following error and I'm not sure why.

The code I am using is as follows;

  
@Stateless(name = "accountService")
public class AccountService implements AccountServiceLocal
{
    @PersistenceUnit(unitName = "persistence-local")
    EntityManagerFactory emf;

    @Override
    @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
    public void runAccount()
    {
       
        EntityManager manager = emf.createEntityManager();

        try
        {
            manager.getTransaction().begin();
            AccountNumber number = new AccountNumber();
            number.setAccountNumber(45987564);
            Card card = new Card();
            card.setAccountNumber(number);
            manager.persist(card);
            manager.getTransaction().commit();
        }
        finally
        {
            manager.close();
        }

    }
}

My persistence.xml file is as follows;

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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_2_0.xsd">

  <persistence-unit name="persistence-local" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <non-jta-data-source>jdbc/sample</non-jta-data-source>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <shared-cache-mode>NONE</shared-cache-mode>
    <properties>
      <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
      <property name="hibernate.dialect" value="org.hibernate.dialect.DerbyDialect"/>
      <property name="hibernate.show_sql" value="true"/>
    </properties>
  </persistence-unit>
</persistence>
 

The main point is when I have the @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED) annotation on the runAccount() method I get the following Exception;

Caused by: org.hibernate.HibernateException: Unable to resume previously suspended transaction
        at org.hibernate.engine.transaction.Isolater$JtaDelegate.delegateWork(Isolater.java:147)
        at org.hibernate.engine.transaction.Isolater.doIsolatedWork(Isolater.java:67)
        at org.hibernate.engine.TransactionHelper.doWorkInNewTransaction(TransactionHelper.java:74)
        at org.hibernate.id.MultipleHiLoPerTableGenerator$1.getNextValue(MultipleHiLoPerTableGenerator.java:216)
......
  

However, if I remove the @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED) annotation (which defaults to TransactionAttributeType.REQUIRED) the method works as expected.

My problems is I don't understand why adding @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED) annotation would cause the exception as I was under the impression that a Resource-Local Entity Manager does not have to use JTA or container managed transactions and therefore if a container managed transaction was not present (using the NOT_SUPPORTED option) it shouldn't matter. What also adds to my confusion is in the stack trace I see a reference to a org.hibernate.engine.transaction.Isolater$JtaDelegate.delegateWork(Isolater.java:147) class which refers to a JTA delegate and reinforces my belief that JTA is still involved in the Resource-Local transaction.

I would be very appreciative of your help and comments and let me know if I have missed something elementary here.

Thanks in advance.