Hibernate4 JPA and JDBC

[fan]

We want to migrate from hibernate 3 to hibernate 4. The main reason being the envers integration.

Part of our application performs jdbc calls via iBatis (via an external bpm product: activiti),
the other part access the database via jpa.

Everything worked fine with hibernate 3.

I guess we have to change something in the configuration in order to make it work.

This the pertinent part of the config

  <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="database" value="db2"/>
                <property name="databasePlatform" value="ch.foo.dialect.DB2zOSDialect"/>
            </bean>
        </property>
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.dialect">ch.foo.dialect.DB2zOSDialect</prop>
                <prop key="hibernate.hbm2ddl.auto">false</prop>
            </props>
        </property>
        <property name="persistenceXmlLocation" value="classpath:META-INF/foo-persistence.xml"/>
    </bean>

    <bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
        <property name="jndiName" value="java:comp/env/jdbc/foo"/>
        <property name="resourceRef" value="true"/>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>

and the foo-persistence.xml

 <persistence-unit name="foo" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <mapping-file>META-INF/foo-orm.xml</mapping-file>
  </persistence-unit>

What I could observe
Activiti checks the database by calling these 2 methods one after the other:

  In Class org.activiti.engine.impl.db.DbSqlSession
  DatabaseMetaData databaseMetaData = connection.getMetaData();  // line 689
  tables = databaseMetaData.getTables(..)   // line 708

The getTables returns null, hiding a NullPointerException thrown in org.hibernate.engine.jdbc.internal.proxy.Connectio nProxyHandler#getResourceRegistry.

The connection.getMetaData() goes through org.springframework.jdbc.datasource.TransactionAwa reDataSourceProxy.TransactionAwareInvocationHandle r#invoke
where a connection is retrieved and released.

The connection (logicalConnection) is hold in the org.hibernate.engine.jdbc.internal.proxy.Connectio nProxyHandler.

The getTables will try to retrieve the connection from the ConnectionProxyHandler, which will fail with a NullPointerException.

Workaround
I could workaround the problem by patching org.hibernate.engine.jdbc.internal.proxy.Connectio nProxyHandler#continueInvocation.
The result of method (getMetaData()) is wrapped in the ConnectionProxyHandler. By removing the wrapping I got back the expected behavior (Well I'm not sure of that as I don't know why it was wrapped in the first place)

   Object result = method.invoke(extractPhysicalConnection(), args);
   // result = postProcess(result, proxy, method, args); <-- patch, commented : line 139

I can't live for long with a patched Hibernate version.
My guess is that I have to change something in the config.
I tried a few things, but I don't have any more ideas

The question
The final question how can I configure hibernate 4 so that my use case works?

Thanks

Spring version: 3.1.1
Hibernate version: 4.1.4
Tomcat 7.0.23

[fan]

I found it out. The problem is how the

org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy

class was initialised.
The

setReobtainTransactionalConnections();

method was called with value 'true'
I just let the default value and everything works fine