This forum is actually dedicated to development processes (like RUP, XP etc.).

I don't think so. I think different contexts don't share anything. Even if the two web apps were both in the same context, their sessions are still not shared between them.

But if they were both in the same context, at least you could have the first app explicitly add some info about itself, to an attribute of the servlet context (you'd have to maintain some kind of "session info cache", adding info for new or updated sessions, and removing info for invalid sessions somehow), so the second app could read it from there.

I'd thought about doing this (but had no time, so it's put off for now), experimenting with developing some kind of session info cache in the servlet context, so that a "monitoring" app could provide status reports for admin use, about the current state of the actual customer app.