you should look at CommitOption (C ? ).
there's no built in way to notify jboss that your db has changed. If you use commit option = B or C you will reload within each transaction so will pick up changes to already loaded entities. Any commit option should pick up new/removed rows in the db (at least if you aren't using findByPrimaryKey, which with option A may look in the cache first and assume it is correct, I'm not sure one way or the other about this.).
There may be some way to send a notification using e.g. java stored procedures in Oracle or something attached to Firebird/Interbase events that "something changed". However all such schemes are at best extremely difficult to get fully synchronized so that your application is guaranteed to be notified of any change before it tries to use the old version of the data.
thank you very much fbiaggi and davidjencks, I am going to try your solution.
Have a nice WE...