I'm not sure if I should be looking at
threads that are currently in
"runnable" state only or if "waiting
on condition" and "in Object.wait" are
also important.
The latter two are actually the things to look for when diagnosing a deadlock, as you seem to be doing. "Runnable" means the thread is doing something right now (or waiting to get the CPU). "blocked" and "waiting" is what deadlocks are made of.
Of course, an application container will have plenty of threads waiting legitimately. To filter out the interesting cases, look at the stack trace. If it's framework classes (and especially ones called "Worker" or "Queue") it's probably OK. If it's application code, you should look at it more closely.
