Error javax.json.stream.JsonParsingException: when making an AJAX API call

I have developed a web based program using java jersey in my back end and jsp in my front end. When I make a post API call using Ajax my back end gets the following exception.

javax.json.stream.JsonParsingException: Unexpected char 117 at (line
no=1, column no=1, offset=0)

I guess it's something wrong with the data which I'm passing through the Ajax API call.

Here is my ajax API call:

var obj = JSON.parse('{ "userName":"John", "password":"hgvv", "img":"New York","fname":"kjbjk","lname":"bkbkkj","tp":"buhb","address":"jhbjhb","type":"user"}');


$.ajax({
    type: "POST",
    url: $url,
    contentType: "application/json",
    data: obj,
    dataType: 'json',
    success: function () {
        alert("successed");

    }
});

This is my back end implemented code:

@Path("testing")
public class test {
	UserRepository userRepo=new UserRepository();
	@Path("users")
	@POST
	@Consumes(MediaType.APPLICATION_JSON)
	@Produces(MediaType.APPLICATION_JSON)
public UserModel CreateUser(UserModel a) {
	userRepo.createUser(a);
	return a;
 }
}

You should send the data as a JSON String, not a JSON Object. Avoid the JSON.parse from your code.

var data = '{ "userName":"John", "password":"hgvv", "img":"New York","fname":"kjbjk","lname":"bkbkkj","tp":"buhb","address":"jhbjhb","type":"user"}';

Alternatively, I would construct the JS Object, and apply JSON.stringify on it. This way, the code is more readable:

var data = {
    userName: "John",
    password: "hgvv",
    img: "New York",
    fname: "kjbjk",
    lname: "bkbkkj",
    tp: "buhb",
    address: "jhbjhb",
    type: "user"
};

$.ajax({
    type: "POST",
    url: $url,
    contentType: "application/json",
    data: JSON.stringify(data), // added JSON.stringify here
    dataType: 'json',
    success: function () {
        alert("successed");
    }
});