consider the following process:

state1+timer -> state2+node-enter:action

The ActionHandler class which is executed as a result of the timer moving the token forward runs into a serious problem, eg. a NoClassDefFoundError.

As a result, the JobExecutorThread which has been executing this timer is killed: Exception in thread "JbpmJobExector:127.0.0.1:1", and eventually no JobExecutorThreads are left to execute timers.