I had the same problem while accessing an Oracle table through a DB link and I finally found a solution with a little help from an Oracle expert. The Oracle DB (on the DB server) must be configured to run as a shared server instead of dedicated server (see init.ora, sqlnet.ora). The use of a shared server can also be forced in the datasource definition by by including a full connect string as the jdbc url. This must the include then string "(SERVER=SHARED)" Maybe this might help, tof (Christof Vollrath) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3984854#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...