WARN [com.mchange.v2.async.ThreadPoolAsynchronousRunner] (Timer-1) com.mchange.v2.async.ThreadPoolAsynchronousRunner $DeadlockDetector@26d6221b -- APPARENT DEADLOCK!!!(line breaks added for readability)
I'm sure there might be more than one reason for this. However, in my case what caused it was duplicate c3p0 declarations - I had them in two places:
- persistence.xml file
- dogs-ds.xml file (JBoss data source file)
The solution was to remove these lines from persistence.xml (which makes sense since the data source declaration is JBoss' job):
<property name="hibernate.c3p0.max_size" value="100" /> ...
No more deadlock!