I’m afraid we no longer have any funded activity to maintain HepRApp.
If anyone with Java expertise wants to offer to update the package to work with newer Java versions, I can share the source code with them.
But I don’t have the capacity to do this work myself at this time.
HepRApp indeed contains Corba capabilities, due its past use as a client-server event display for physics collaborations. As Corba is not supported in the newer Java versions, it gives this error. We would need a new Java expert to step up, omit the Corba parts of the code (should not be very difficult), and then re-build for the newer Java. As I have not touched Java development myself in many years, it would take me significant time to ramp up to do this task, and I just don’t have funded time to do that work.
Most of the capabilities that were present in HepRApp are also nicely supported by the Geant4 Qt GUI, so I would recommend most users switch to Qt for the kind of interactive capabilities they previously had in HepRApp.