For the JBoss Application Server and our applications to use the external database, we also need to install the database's JDBC driver. The JDBC driver is a JAR file, which you'll need to copy into your JBoss AS's <JBoss_Home>/server/all/lib directory. Replace all with the server configuration you are using if needed. This file is loaded when JBoss starts up. So if you have the JBoss AS running, you'll need to shut down and restart. The availability of JDBC drivers for different databases are as follows.