Correct me if I'm wrong, but I seem to recall that you had two processors in your servers, and any java thread would run on only one of them... Is all of the processing done on one thread or does downtime only happen when two (or more) threads are maxed out?

Anyway, killing those threads after given time-out is probably not a good idea, as there might be other reasons for 100% cpu usage (like: a lot of users - killing the thread would only make things worse). Of course if that's all that can be done, then that's what must be done... :(

I'd really love to try and help you out, but:
a) I don't have the time
b) I don't know enought of your system
c) you seem quite competent your self :D

Thanks for the site anyway. Maybe some day I'll even pay something (for the record, the reason I'm not a paying member is that I don't like to pay on the net with anything except Nordeas "button payment" - and that's only implemented here in Finland, possibly in some other northern european countries too). :)

Nope, only one of them. But thanks to the second processor I am able to handle the deadlock without hard restart of the whole server - which could take up to one hour.
There are no other reasons for 100% CPU usage. I've been monitoring it each day during several months and I know where the problem lies. But, of course, killing threads is only one possibility that can be tried, there are more options, I simply cannot test them all at once :-) You know, this site is not my full-time job.