Java - Nested JSON objects - json

Question

I am trying to create a simple JAVA remote for XBMC/KODI and I think im doing ok so far (still early days) but I have hit a snag when I reached a nested JSON object.
This is the original code I am converting to JAVA:
{"jsonrpc": "2.0", "method": "Player.PlayPause", "params": { "playerid": 0 }, "id": 1}
I have done this in JAVA so far:
public static void main(String[] args) throws UnknownHostException, IOException{
JSONObject json = new JSONObject();
json.put("jsonrpc", "2.0");
json.put("method", "Player.PlayPause");
//json.put("params", "playerid = 0"); THIS IS THE LINE I am having issues with
Socket s = new Socket("192.168.0.21", 8080);
try (OutputStreamWriter out = new OutputStreamWriter(s.getOutputStream(), StandardCharsets.UTF_8)) {
out.write(json.toString());
}}
As you can see from the original JSON there is a nested {} within the {} so {{}} and I dont know how to handle this. Im using JSON-Simple in eclipse if this helps, thanks for any help!
EDIT:
So that was helpful thanks, but it doesnt actually work is there anything wrong with the syntax:
public static void main(String[] args) throws UnknownHostException, IOException{
JSONObject json = new JSONObject();
JSONObject params = new JSONObject();
json.put("jsonrpc", "2.0");
json.put("method", "Player.PlayPause");
params.put("playerid", 0);
json.put("params", params);
json.put("id", 1);
Socket s = new Socket("192.168.0.21", 8080);
try (OutputStreamWriter out = new OutputStreamWriter(s.getOutputStream(), StandardCharsets.UTF_8)) {
out.write(json.toString());
}
}

Answer 1

Create another JSONObject for the params, set it up, and add it to the parent JSONObject with the key params.

Answer 2

//import java.util.ArrayList;
//import org.bson.Document;
Document root= new Document();
Document rootParams = new Document();
root.append("jsonrpc","2.0");
root.append("method","Player.PlayPause");
rootParams.append("playerid",0);
root.append("id",1);
if (!rootParams.isEmpty()){
root.append("params",rootParams);
}
System.out.println(root.toJson());