Stunner & Forms - not possible to execute process with ArrayList process variable

1. Import BPMN2 file exampleProcess.bpmn2 (for now only in old Designer), save and deploy create process click “import from BPMN2” select attached file 2. Go to Process Definitions, start process You will see Click Submit, you will see two errors process not started. In server log I see an error: error.log 3. Undeploy KIE-Server, open Business Process again Try to generate all forms in server log you can see: ```17:31:20,220 ERROR [org.jbpm.designer.web.server.TaskFormsServlet] (default task-124) java.lang.NullPointerException``` 4. Close business process, add new form using Add Asset and generate forms for the process Empty form will be created Build and deploy project again Start process Click Submit button Process will be successfully started and executed Expected Result: 1. If use try to generate form he/she will get empty form, or form with some basic type, like int, String and so on and missed variables like ArrayList. 2. If user didn't generated forms he/she will be able to use process as he/she generated default forms. Another option - show readable notification "Please, generate form first".