Depends on the type of clients that would access the Java/J2EE equivalent of your CORBA service.
Some pointers..
1. If your client is going to be a pure
java client,consider writing an RMI service
2. If you want to keep the service accessible to the existing CORBA clients,consider implementing the CORBA service using EJBs
3. For any generic client,consider exposing a Java based web service over
SOAP
-Ajay