Hi! I have a flow where I call external webservices parallel from my own WorkItemHandler. I have a ExecutorService and in executeWorkItem I submit a Callable what does the work, so executeWorkItem return immediately. The Callable calls workItemManager.completeWorkItem after the work is done. As far as I can judge it works but I see the following problems: - Is the workItemManager threadsafe? Can i call completeWorkItem() from a other thread? - In the parallel threads I do a ksession.insert(). Is this safe? - Should I wrap the StatefulKnowledgeSession in a thread safe wrapper? - fireAllRules does not wait for the process to finish but returns immediately so I have to use fireUntilHalt. This uses one CPU core completely. My solution is: ProcessInstance prc = ksession.startProcess("Main"); while (prc.getState() == ProcessInstance.STATE_ACTIVE) { Thread.sleep(100); ksession.fireAllRules(); } Is this OK or is there a better solution? I dont like polling ;-(. Thanks! juergen -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Implementation-proble... Sent from the Drools - User mailing list archive at Nabble.com.