Buat Apa [http://community.jboss.org/people/buatapa] created the discussion "How to revisit an old state in jbpm 3.2.8?" To view the discussion, visit: http://community.jboss.org/message/574799#574799 -------------------------------------------------------------- I tried the followings using jbpm 3.2.8. When I end with "no", which should go back to the previous state (*submitForm)*, but I got the following errors occasionally. Did I do something wrong, or what is the right way? Caused by: java.util.ConcurrentModificationExceptionat java.util.HashMap$HashIterator.nextEntry( HashMap.java:793 )at java.util.HashMap$KeyIterator.next( HashMap.java:828 )at org.hibernate.collection.AbstractPersistentCollection$IteratorProxy.next( AbstractPersistentCollection.java:555 ) java code (I am in open approveForm state) Collection taskList = processInstance.getTaskMgmtInstance().getTaskInstances(); Iterator<?> iter = taskList.iterator(); *while* (iter.hasNext()) { TaskInstance taskInstance = (TaskInstance) iter.next(); *        if* (taskInstance.isOpen()) {                taskInstance.*end*(approve ? "yes" *:**"no"*);        } } ...... process definition code <start-state name="start">   <transition to="submitForm"></transition> </start-state> <task-node name="*submitForm*">   <task name="submitForm">    <assignment actor-id="submitter"></assignment>   </task>   <transition to="approveForm"></transition> </task-node> <task-node name="approveForm">   <task name="approveForm">    <assignment actor-id="approver"></assignment>   </task>   <transition to="end" name="yes"></transition>   <transition to="*submitForm*" name="*no*"></transition> </task-node> <end-state name="end"> </end-state> -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/574799#574799] Start a new discussion in jBPM at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]