How do I convert a JSONObject to class object?

Here's a tutorial for GSON - I think it should help bolster your understanding. Essentially the parsing is done like this:

String mJsonString = "...";
JsonParser parser = new JsonParser(); 
JsonElement mJson =  parser.parse(mJsonString);
Gson gson = new Gson();
MyDataObject object = gson.fromJson(mJson, MyDataObject.class);

if you still want to use org.json.JSONObject:

org.json.JSONObject o;
ObjectMapper m = new ObjectMapper();
MyClass myClass = m.readValue(o.toString(), MyClass.class);