If you are starting a new project, you should be using JBoss Messaging. The documentation should outline some of the features and differences between it an JBossMQ. You will have to download and install JBoss Messaging if you are using JBossAS 4.2.2. (For JBossAS 5.0, JBoss Messaging is already provided.) Looking at JBoss 5.0.0.Beta4, you can make the same changes by editing the file server/default/deploy/messaging/hsqldb-persistence-service.xml. Finally, if you plan on moving your app to production, you will need to use a database other than Hypersonic. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4144918#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...