Which version u r using?With jboss-3.2.1 and latter u will find embedded hybersonic DB.
I'm using JBoss 3.2.5. It has Hypersonic embedded, I created some tables using Database Manager but the problem is how to connect to it in Java application?
Is your application running inside JBoss?
If so you do not need to use the traditional JDBC aproach to obtain connect to the database, instead you need to look up the DataSource using JNDI.