Mapping angular Scope object to Java RestController

I am having a scope Object in Angular Controller.

When I try to pass it onto Spring Rest Controller , the control is passed to Spring rest controller. But when I try to print the value its getting printed as null.

Scenario:

AngularController :

file.upload = Upload.upload({
    url : '/uploadTemplate',
    data : {
        multipartFile : file,
        am : appMaster
    }
});

RestController.java

@RequestMapping(value = "/uploadTemplate", produces = "application/json")
@ResponseBody
public StringResponse uploadFiles(MultipartFile multipartFile,ApplicationMaster am) {
        System.out.println("Inside");

        System.out.println(am.getAbbreviation());
        System.out.println(am.getAppId());
        System.out.println(am.getName());
}

The first System.out.println Inside is getting printed in console , but next the values of am object are printed as null.

If I alert the values in AngularController , the desired values are alerted.