jquery FormData not working with Servlet

Question

I am sending one file to the tomcat server using jQuery FormData. The file is being received successfully on the server but any other value which I send with the file is not being received. For processing the file upload, I am using http://commons.apache.org/proper/commons-fileupload/ and http://commons.apache.org/io/. It is getting my file somehow. But when I write

request.getParameter("file")

in the servlet for the below code, it returns null. Even it doesn't show any parameter in the request object. I don't understand how it gets the file then. Can anyone help me to solve this?

$('#uploadCourseDetail').click(function() {
    var form_data = new FormData();
    if (!($('#courseDetails').prop('files')[0] == undefined)) {
        var file_data = $('#courseDetails').prop('files')[0];
        form_data.append('file', 'examdetail');
        form_data.append('courseDetails', file_data);
    }
    $.ajax({
        url: 'Exam_TimeTable_Scheduler_bySlots_Web_Project/FileUploadServlet',
        type: 'POST',
        contentType: false,
        processData: false,
        cache: false,
        data: form_data,
        success: function(data) {
            alert("File Uploaded Successfully !");
        }
    });
});

I use firebug to track the requests. It shows that both the fields are being sent to the server. Below is the snapshot for the same:

Answer 1

There was a mistake in my backend code. Above code works perfectly. Sincere apologies for the wrong post!