How to replace value in json file

You can try this with simple json library(library) . I am separately printed all object for understanding. AS you declare Id object inside two more object, so firstly you have to get this object then get your desire object IDNew. Then put new id value in id field.

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

public class Main {

    private static final String filePath = "E:\\project-test\\scloud\\test\\src\\main\\resources\\test";

    public static void main(String[] args) {

        try {
            // read the json file
            FileReader reader = new FileReader(filePath);

            JSONParser jsonParser = new JSONParser();
            JSONObject jsonObject = (JSONObject) jsonParser.parse(reader);

            System.out.println(jsonObject);


            JSONObject addedObj = (JSONObject) jsonObject.get("Added");
            System.out.println("Added is: " + addedObj);

            JSONObject newmemObject =(JSONObject) addedObj.get("newmem");
            System.out.println("newmemObject is: " + newmemObject);

            JSONObject idNewObj =(JSONObject) newmemObject.get("IDNew");
            System.out.println("IdNewObj is: " + idNewObj);

            long id =Long.valueOf((String) idNewObj.get("id"));
            System.out.println(id);


            idNewObj.put("id",809809809);

            System.out.println(jsonObject);

        } catch (FileNotFoundException ex) {
            ex.printStackTrace();
        } catch (IOException ex) {
            ex.printStackTrace();
        } catch (ParseException ex) {
            ex.printStackTrace();
        } catch (NullPointerException ex) {
            ex.printStackTrace();
        }

    }

}

Or for simplicity you can use this

    FileReader reader = new FileReader(filePath);
    JSONParser jsonParser = new JSONParser();
    JSONObject jsonObject = (JSONObject) jsonParser.parse(reader);
    System.out.println(jsonObject);

    JSONObject idObj = (
       (JSONObject) (
             (JSONObject) (
                (JSONObject)
                   jsonObject.get("Added")
             ).get("newmem")
       ).get("IDNew")
    );

    idObj.put("id", 98009809);
    System.out.println("After ID value updated : "+jsonObject);

You can update a nested element in a JSONObject using the simple-json java lib as follows:

JSONObject added = (JSONObject) data.get("Added");
JSONObject newmem = (JSONObject) added.get("newmem");
JSONObject idNew = (JSONObject) newmem.get("IDNew");
idNew.put("id","12345678");
System.out.println(data);