The hsqldb-ds.xml file contains three connection-url entries, two of which must always be commented out, and one of which must always be uncommented. The one that is not commented out determines the behavior. In all cases, all of the database data is kept in memory while running. The default one (the third one, "in-process persistent db") causes Hypersonic to write the database contents to the file server/xxx/data/hypersonic/localDB.script when the app server halts. This script is used when the app server starts again to initialize the database. If you use the second one ("not saved when jboss stops"), Hypersonic will not write the localDB.script file. So every time the app server starts you get a clean, empty database. The first one ("For server mode db") start Hypersonic in a separate process, and all database access goes over TCP. Other than that, I behaves much like the third option - the localDB.script file is created when Hypersonic is stopped. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4180338#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...