The fix for 4289544 has caused an incompatibility for an activatable object whose class is in the extension classloader or the boot classloader, but wants to allow class resolution during unmarshalling on incoming calls against classes in the system classloader (and in the extension classloader, if the service class is in the boot classloader). ActivationGroupImpl simply sets the context classloader to the classloader of the service class, rather than sticking with the current context classloader (in this case, the system classloader) if it happens to be a child of the service's classloader, which would be consistent with the context classloader choice made at export time.