java app deadlock but unlocked after use jstack to dump thread

Question

My java app is sometime freezing so I dump thread with jstack -F but the report show no deadlock and app became responsive again ? anyone know what happened ?

My app using hibernate 4.1.8, jetty 9M2, mysql connector 5.1.22, c3p0 0.9.2.pre6. the thread dump seem blocked everywhere: the log file is a bit long so I uploaded it here http://pastebin.com/vDCd6Kjb

Answer 1

found this in doc

The process is suspended when this connector attaches and resumed when this connector detaches.

back to find where the deadlock is