If you are using the JBoss-MySQL turnkey, I would try two things:
1) if you are using the 3.x version of the MySQL JDBC driver replace it with a 5.0.x version
2) take a look at the data source sample posted at http://blogs.adobe.com/livecycle/adobe-ds.xml
thank you for your answer. Unluckly i'm not using mysql but oracle 9i (or 10i i don't know since i'm just a poor programmer). Anyway i did a test : i've bypassed the datasource file , hardcoding the connection parameters in my custom component and it has got executed without problem, then process has crushed again on a query done by some adobe component. there are many adobe sql component instances to read/write from the same schema my compnent uses, so i suppose the problem is inside datasource configuration. There's a datasource sample for oracle too?
I cannot give much details, since the new system has been recently installed and i don't know all info (i think jboss is 4.2 but i'm not sure)
A sample Oracle data source file is shipped with LiveCyce ES. If you look at the root of the installation folder you should find
It is attached, also.