How can client determine cause of RemoteException

Question

My BMP entity bean includes an SQL statement to UPDATE a database row (this UPDATE is in the ejbStore method).
The UPDATE statement includes the following syntax
UDPATE ....
SET ....,
no_of_changes = :no_of_changes + 1
WHERE ....
AND no_of_changes = :no_of_changes
This ensures the UPDATE only proceeds if no other user has updated the row between my ejbLoad and ejbStore.
If the update fails, becuase another user has updated the row, I throw an exception DatabaseBusyException, which extends RemoteException.
My problem is that my client only sees a RemoteException, and I am therefore unable to be sure what message to give to the client. Ideally I would be able to tell it was a DatabaseBusyException and would inform the user that the 'Database is busy. Please retry later'.
Any suggestions?

Answer 1

Hmm, not sure on this. If the session bean is using remote access (PortableRemoteObject.narrow), then yes, all exceptions to the client are wrapped in Remote. But you should be able to get the exception message straight from remote - I'm not sure about the originating exception type, e.g. MyException.
I must admit I've been focusing more server side so far, and the limited client side stuff I've done seems to indicate that remote simply passses the exception message. I don't think remote is being wrapped twice as you suggest, also not sure why you feel you need to trundle through the exceptions to the original message. I'm getting exceptions thrown from the SQL level in the EJB right up to the client (through several other session bean layers), and the original exception details are being preserved in the message body. EMail if you want to discuss further off-line.
Rgds, LB