1) Whenever a gateway is used it is mandatory to specify the type like OR, AND, XOR.
2) Before starting on teh process design, specify an ID for process. Once you start adding components, a BPMN plane is created and it takes the id of the process, which if not specified is null and fails against the rule flow xml standards, and hence the null message.
I have a different problem but on the same topic.
The editor works fine but when i add the bpmn2 file to a KnowledgeBase i have this exception:
java.lang.IllegalArgumentException: Unknown gateway direction: Converging
I have this exception only with Inclusive Gateway, and only with Converging direction.
is it a bug or only I have this problem?