Horst Leitenmueller [https://community.jboss.org/people/horstL] created the discussion "Re: driver-class makes no difference" To view the discussion, visit: https://community.jboss.org/message/739803#739803 -------------------------------------------------------------- hi, i possible have a answer for your problem, because i have the same problem on a jboss 5.1.0.GA to use actual p6spy you have todo 2 things: 1. add set in spy.properties   useprefix to true 2. add in -ds.xml to the connection-url  the prefix "p6spy:"jdbc:mysql...  (without quotes) problem behind if you are interessted is the loading mechanism of LocalManagedConnectionFactory.getDriver(final String url) which is not checking the driver-class entered only if real loaded for the first time but afterwards only the url is checked ! // Check if the driver is already loaded, if not then try to load it if (isDriverLoadedForURL(url))       { return driver;       } // end of if () i hope the answer helps, br horst -------------------------------------------------------------- Reply to this message by going to Community [https://community.jboss.org/message/739803#739803] Start a new discussion in Datasource Configuration at Community [https://community.jboss.org/choose-container!input.jspa?contentType=1&...]