There are two different SMPC code snippet from the two seam examples: <persistence:managed-persistence-context name="entityManager" | auto-create="true" | persistence-unit-jndi-name="java:/dvdEntityManagerFactory" /> <persistence:entity-manager-factory installed="@seamStartsPersistenceUnit@" | name="wikiEntityManagerFactory" | persistence-unit-name="wiki"/> | <persistence:managed-persistence-context name="entityManager" | auto-create="true" | entity-manager-factory="#{wikiEntityManagerFactory}" | persistence-unit-jndi-name="java:/entityManagerFactories/wiki"> | </persistence:managed-persistence-context> The second define an entity-manager-factory and use it in the managed-persistence-context.I want to know when the entity-manager-factory is needed. I searched in the reference,found it in the three place: spring oc4j special components but I cann't figure out it's really usage. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4110408#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...