Yes, without the isolated class loader I was able to deploy the RAR in the EAR, then seperately deploy the -ds.xml using the ear# syntax. INFO org.jboss.resource.connectionmanager.ConnectionFactoryBindingService Bound ConnectionManager 'jboss.jca:service=ConnectionFactoryBinding,name=index_connection_factory' to JNDI name 'java:index_connection_factory' So, does that give me a legitimate reason for putting the -ds.xml in the EAR too? So that it can see the EARs classes. This brings me back to my original question, is it possible to deploy the EAR and RAR (and -ds.xml) seperately using isolated class loaders and call-by-value semantics (to avoid the class cast exceptions)? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3963034#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...