Java Persistence API: Multiple Persistence Units problem

[Aurelio Calegari]

Hi Ranchers,

I'm working with Java EE 5 and using the Java Persistence API 1.0. I have two databases, one db2 and one mysql. The connection to them are set properly and I have one table in each of these databases. I also have one Entity class for each table. The issue is that I'm getting troubles to connect both dbs in one operation. Here's my persistence.xml file:

<?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 <a href="http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">" target="_blank" rel="nofollow">http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"></a>
  <persistence-unit name="MySQL-ejbPU" transaction-type="JTA">
    <jta-data-source>jdbc/mySqlDB</jta-data-source>
    <class>ejb.model.MySQLTable</class>
    <exclude-unlisted-classes>true</exclude-unlisted-classes>
    <properties/>
  </persistence-unit>
  <persistence-unit name="DB2-ejbPU" transaction-type="JTA">
    <jta-data-source>jdbc/MyDB2DB</jta-data-source>
    <class>ejb.model.MyDB2Table</class>
    <exclude-unlisted-classes>true</exclude-unlisted-classes>
    <properties/>
  </persistence-unit>
</persistence>

And here's my session facade:

@Stateless
public class TablesFacade implements TablesFacadeRemote {
 
    @PersistenceContext(unitName="MySQL-ejbPU")
    private EntityManager emMySql;
    
    @PersistenceContext(unitName="DB2-ejbPU")
    private EntityManager emDb2;
    
    (...)
    public void create(MyDB2Table db2, MySQLTable mySql){
    emMySql.persist(mySql);
    emDb2.persist(db2);
    }
    (...)
 }
 

I'm getting the following exception:

 RAR5027:Unexpected exception in resource pooling 
 java.lang.IllegalStateException: Local transaction already has 1 non-XA Resource: cannot add more resources.  
         at com.sun.enterprise.distributedtx.J2EETransactionManagerOpt.enlistResource(J2EETransactionManagerOpt.java:111)
         at com.sun.enterprise.resource.SystemResourceManagerImpl.enlistResource(SystemResourceManagerImpl.java:87)
(...)

I'm wondering if this problem is related to the fact I want both to be container managed... Any ideas on how to resolve this?

Thanks in advance

Aurelio

[Edvins Reisons]

The exception you are getting means that your database connections do not support distributed transactions. Check the drivers for XA compliance, and see, for example, this discussion.