I have the following resource (implemented using Spring 4.05.RELEASE) which accepts a file and a JSON object:
(P.S. activityTemplate is a serializable entity class)<
The default content type is 'application/octet-stream'. Since you are uploading jar file and JSON the content type should be set in the @RequestMapping annotation as follows:
@RequestMapping(value="/create", method=RequestMethod.POST, headers="content-type=application/json,application/java-archive")