There were 2 main reasons why i opted to improve our own implementation over Quartz : 1) a very heavy integration layer was needed between quartz and jbpm. especially making sure that quartz was using our jdbc connection for user job operations required some tricks. apart from that, there was more jdbc connection management going on in quartz which was hard to tie to our hibernate integration. 2) quartz can't acquire job-locks be means of optimistic locking. only pessimistic locking is supported and that is not supported by all databases (i.e. hsqldb). the solution that we now have worked out can acquire exclusive locks on a job by using hibernate's optimistic locking. this should even work with isolation level 0 (READ_UNCOMMITTED), which is the only level supported by hsqldb View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3968946#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...