If I ever debug NotesThread initialization and termination again, shoot me.
Overhaul again of the .threads package to try to get Xots right. It's working now on hundreds of concurrent and sequential operations without triggering panics on a JVM shutdown.
Dear IBM: the HTTP JVM should honor shutdownHooks on a "tell http quit" command. And I bet this is the source of your crashy problems on Traveler. There's probably a ThreadPoolExecutor trying to use a shutdownHook to clean up threads that have accessed Domino APIs.
Please FIX YOUR BROKEN JVM.
DominoExecutors that created under the XPages or DOTS JVMs will clean up via an Activator.stop() call, but Executors created in other contexts like Java addins or Agents must be sure to call .shutdown() themselves.

I'm going to have a tall glass of tequila now.