Android : Android Custom Canvas

How to put this in json format.

{
    "caller-id": "2434141414",
    "map-id": "2",
    "src": {
        "x": "23",
        "y": "34"
    },
    "dest": {
        "x": "23",
        "y": "34"
    }
}

I tried like this :

JSONObject src = new JSONObject();
        JSONObject dest = new JSONObject();
        src.put("src", mObjUserPath.get("x1"));
        src.put("src", mObjUserPath.get("y1"));
        dest.put("dest", mObjUserPath.get("x2"));
        dest.put("dest", mObjUserPath.get("y2"));
        json.put("caller-id", Util.getDeviceID(this));
        json.put("map-id", RestClientAsyncTask.mapId);
        json.put("src", src);
        json.put("dest", dest);

but is not in format what I expected.Please help Any help will be appreciated!