How can I get a process instance to cancel itself after 24 hours? I have a process that should only last for a day...after which the tasks and all states must be closed/ended.
This is not possible from within the jBPM, at least not automatically. You could create a scheduler on the process-start event (I think) which runs for 24 hours and than cancels the process instance. You could also do it externally from another scheduler. But then it is not the process-instance.