Joining all non-daemon threads

[Patrick Doyle]

I'm wondering how JVMs implement non-daemon threads.  The VM must join all
active non-daemon threads before it exits, so that the VM doesn't exit
until all non-daemon threads terminate.  Then, I gather, when all
non-daemon threads are done, it must terminate all daemon threads and then
exit.

What's the easiest way to implement this?  Does ThreadGroup provide enough
functionality to do it?  Or do I have to maintain a list of active threads
myself?  Does Classpath have any additional functionality to support this?

--
Patrick Doyle
address@hidden