it seems that if you want to use annotations and ejb-jar.xml (e.g. if you want to define your MDB with annotations, but specify the destination in ejb-jar.xml), you must include the <message-destination-type> tag in ejb-jar.xml, otherwise you get the "Unable to create activation spec ...." exception. Don't know why, but it works. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3962635#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...