Question: has anyone seen the following before? [This is with 'All' config JBoss 4.2.1GA. and Spring 2.1M4 and Toplink Essentials JPA 2.0-b58g] | 14:36:08,158 ERROR | [org.jboss.web.tomcat.service.session.JBossCacheService] | externalizeSession(): exception occurred externalizing session | SessionBasedClusteredSession[id:ZhOYIR+Pdkv7GkUG3bjcsg** lastAccessedTime: 1192509366298 version: 3 lastOutdated: 0] | java.io.NotSerializableException: | org.springframework.orm.jpa.AbstractEntityManagerFactoryBean$ManagedEntityManagerFactoryInvocationHandler | at | java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1081) | at | java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375) | at | java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream | Why should the EntityManager stuff be serialized into the session anyway...doesn't make any sense to me! As always, enlightenment very gratefully accepted. Cheers, Alph View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4095560#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...