Distinguish different exceptions from server?

Question

hi,
In my application, there is a remote call:
public Object getXXXX
throws RemoteException, MyExceptionA, MyExceptionB;
(where MyExceptionA and MyExceptionB are both child class of RemoteException)
I have two related questions.
1. On the client side, it will always get the java.rmi.ServerException
NO MATTER what the server code actually throws, i.e, EVEN IF server
throws MyExceptionA (or B), the client will still get ServerException.
Is that always the case?
2. If it is always the case, then in client code, what is the best
practise to distinguish different exceptions?
Do I have to catch ServerException first and then use
ServerException.getCause() and then use instanceof to know exactly
which exception was actually thrown by the server? That seems to
be a little bit clumsy. Are there any other elegant ways to know
the EXACT exception thrown by server?
Thanks in advance for the help.
JK

Answer 1

The above argument makes perfect sense to me. But, it
seems
to me, no matter how many kinds of exceptions you
declare in
the signature of your remote call, assuming the remote
call gets
to the server and gets executed on the server, if any
exception
occurs on the server, the client will ONLY get ONE
exception:
java.rmi.ServerException (see my original question 1)
Is that REALLY the case or NOT?No, it is not the case. You only get a ServerException if a RemoteException happens on the server: 'A ServerException is thrown as a result of a remote method invocation when a RemoteException is thrown while processing the invocation on the server, either while unmarshalling the arguments, executing the remote method itself, or marshalling the return value'. In other words you only get a ServerException because of either a failure inside the RMI runtime in the server while setting up or tearing down the call, or if the remote method in the server calls another remote method itself (i.e. calls another server) and gets a RemoteException from that.
If your server deliberately throws an exception because you coded it that way, the client gets the exception thrown. If the server trips an Error you get a ServerError at the client. If the server trips a RuntimeException you get a RuntimeException at the client.
EJP