If you want to use the "totally in-memory db", remove the server/xxx/data directory before bringing up the app server. If you do not do this then the old database will be reloaded. Thus, the "totally in-memory db" option applies during the time the app server is halted, not to when it is started up. I did this, and saw that there was still a server/xxx/data/hypersonic/localDB.script file created, but the file was missing the DDL statements that create tables and the INSERT statements that reload data. This fact that the file still appears tells me that Hypersonic always loads the file, regardless of the url-connection setting. Hence my suggestion to remove the server/xxx/data directory. By the way, "data persist in the memory" is an oxymoron - persisting data means moving/copying data out of memory and to a permanent storage device such as a disk drive. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4180597#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...