You CANNOT connect to an in memory database from outside the process. You must either do the research to figure out how to start HSQL in a mode that does allow external connections or use a database instance running in another process. For the latter, 2 minutes looking at the HSQL docs shows that you can start up a database instance like this: java -cp server/default/lib/hsqldb.jar org.hsqldb.Server -database.0 dbfile -dbname.0 dbname Then you can access the db using this URL: jdbc:hsqldb:hsql://localhost/dbname That is how you access from your app and from the database manager. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3989159#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...