Further observations: The class loader doesn't seem to load the MDB before its first use. I checked that by adding a static initializer to the MDB. If a message arrives in the queue that the MDB is connected to, the static initializer is invoked. The system properties java.naming.provider.url and java.naming.factory.url.pkgs are set correctly in that case, however, the property java.naming.factory.initial is unset, even though the file jndi.properties is in the conf folder of the JBoss installation directory. In my opinion, this is a bug. Even if I add | System.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory"); | to the static initializer, I still get the NoInitialContextException. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4161092#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...