Tomcat isn’t a full application server; it’s just a servlet container, albeit a servlet container with some features usually found only in application servers. One of these features may be used with Hibernate: the Tomcat connection pool. Tomcat uses the DBCP connection pool internally but exposes it as a JNDI datasource, just like a real application server. To configure the Tomcat datasource, you’ll need to edit server.xml according to instructions in the Tomcat JNDI/JDBC documentation. You can configure Hibernate to use this datasource by setting hibernate.connection. datasource. Keep in mind that Tomcat doesn’t ship with a transaction manager, so this situation is still more like a non-managed environment as described earlier.