POST request not getting mapped to Spring MVC Controller

I am sending a POST request from Angularjs $http service . It is working fine when my promise is like below and is getting properly mapped to Spring Controller ,

service.js

reassignKsaPendingLeads : function(data,username)
                                    {
    var promise = $http({
        url : "reassignPendingLeads.htm",
        method : "POST",
        data : mydata
        })
        .success(function(data, status, header, config, statusText)
        {
        }       
}

Spring Controller

@RequestMapping({ "reassignPendingLeads.htm" })
    public @ResponseBody String updateAccessStatus(@RequestBody List<KsaLead> ksaLeads) 
    {
        log.info("Inside updateAccessStatus");
        return "true";
    }        

The json object i pass from service.js is getting mapped properly to @RequestBody List ksaLeads.
Since the json object contains same keys as bean properties of KsaLead.

But Now i want to pass another parameter username apart from json body (data).
Then i get Request method ‘POST’ not supported in Spring Controller .

new service.js

reassignKsaPendingLeads : function(data,username)
                                    {
                                        var mydata = JSON.stringify(data) + '&username=' + username;    
                                        var promise = $http({
                                            url : "reassignPendingLeads.htm",
                                            method : "POST",
                                            data : mydata
                                        })
                                        .success(function(data, status, header, config, statusText)
                                        {
                                        }

new Spring Controller

@RequestMapping({ "reassignPendingLeads.htm" })
    public @ResponseBody String updateAccessStatus(@RequestBody List<KsaLead> ksaLeads,@RequestParam String username) 
    {
        log.info("Inside updateAccessStatus");
        return "true";
    }

Can anyone guide me as to how should i pass data from angularJs so that it gets mapped correctly to Spring Controller

Source: AngularJS