Many organisations use CORBA to support their distributed legacy applications. As far as WebLogic is concerned, here is an example of a sample architecture (using BEA stuff): WebLogic (application) Server supplies access to components through its J2EE facilities. WebLogic (application) Server components connect to the legacy system through a CORBA ORB, which provides language independent access to services. You would wrap your AS/400 legacy app with WebLogic Enterprise Server (assuming BEA provides WLE for AS/400), which provides both EJB support and CORBA services. Your CORBA services would be written in C++ for example and you could interface with C functions therein. It's very possible to tie a WLS system and a WLE system together. If you want to find out more about CORBA, we also have a CORBA/RMI forum here at JavaRanch. I hope that helps.