at the end preferences are stored as strings in the db with an integer which says what data type it is. this is the potential usage as in reality we only use strings because JSR168 does not support more than that (unless you write your extension). what is the interface you are using ? Instance.getProperties() and Instance.setProperties(...) ? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4013382#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...