I found the solution. The database is bound to the servers IP adress, because I have to talk to it from an other server. Therefore in mysql-ds.xml it is wrong to write localhost, though it is the same server. <connection-url>jdbc:mysql://localhost:3306/JbossDB</connection-url> we have to spcecify its IP adress <connection-url>jdbc:mysql://xx.xx.xx.xx:3306/JbossDB</connection-url> View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4048802#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...