Thanks! i tried this but it still does not work. Now i actually get an error at deployment time. Here is my jboss-app.xml <?xml version="1.0" encoding="ISO-8859-1"?> | <!DOCTYPE jboss-app PUBLIC '-//JBoss//DTD J2EE Application 1.3V2//EN' 'http://www.jboss.org/j2ee/dtd/jboss-app_3_2.dtd'> | <jboss-app> | <loader-repository> | jboss.loader:loader=com.thalys.opalys-opalys-server-4.2.5-SNAPSHOT.ear | <loader-repository-config>java2ParentDelegation=false</loader-repository-config> | </loader-repository> | </jboss-app> Is it right? Problem is, my use of activation.jar is in a .jar inside my .ear. And apparelntly, from the Wiki link you gave to me, it is said that nested modules are not taken into account anonymous wrote : There are two levels of scoping, isolation from other deployments, and isolation that overrides the loading of JBoss server classes. With nested modules, only the top level file may specify class loader scoping. If you have a .ear file containing other modules, only scoping specified in the .ear's META-INF/jboss-app.xml is used. And at deployment time, i now get this: anonymous wrote : 15:20:37,979 INFO [STDOUT] 15:20:37,976 ERROR [ContextLoader] Context initialization failed | org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager' defined in ServletContext resource [/WEB-INF/applicationContext-dataSource.xml]: Initialization of bean failed; nested exception is org.springframework.transaction.TransactionSystemException: JTA UserTransaction is not available at JNDI location [java:comp/UserTransaction]; nested exception is org.springframework.jndi.TypeMismatchNamingException: Object [org.jboss.tm.usertx.client.ServerVMClientUserTransaction@a11c08] available at JNDI location [java:comp/UserTransaction] is not assignable to [javax.transaction.UserTransaction] | org.springframework.transaction.TransactionSystemException: JTA UserTransaction is not available at JNDI location [java:comp/UserTransaction]; nested exception is org.springframework.jndi.TypeMismatchNamingException: Object [org.jboss.tm.usertx.client.ServerVMClientUserTransaction@a11c08] available at JNDI location [java:comp/UserTransaction] is not assignable to [javax.transaction.UserTransaction] | org.springframework.jndi.TypeMismatchNamingException: Object [org.jboss.tm.usertx.client.ServerVMClientUserTransaction@a11c08] available at JNDI location [java:comp/UserTransaction] is not assignable to [javax.transaction.UserTransaction] | at org.springframework.jndi.JndiTemplate.lookup(JndiTemplate.java:148) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4124421#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...