Hi,
I moved to jbpm5.4 and it solves the issue since the marshal(..) function only needs 2 arguments now:
I refer to this code
https://github.com/droolsjbpm/jbpm/blob/master/jbpm-examples/src/main/java/org/jbpm/examples/humantask/HumanTaskExample.java
Map<String, Object> results = new HashMap<String, Object>();
results.put(comment, Agreed, existing laptop needs replacing);
results.put(outcome, Accept);
ContentData contentData = ContentMarshallerHelper.marshal(results, null);
taskClient.complete(task1.getId(), sales-rep, contentData);
For JBPM5.3 I am not sure if it can be solved by passing null to second marshal(..) function variable. But maybe you can give that a try.
Regards,
Thomas Setiabudi