JSON File - Java: editing/updating fields values

Simply you can do like this:

import java.io.File;import java.io.FileWriter;import java.io.IOException;import org.json.JSONException;import org.json.JSONObject;import com.fasterxml.jackson.databind.ObjectMapper;public class Test {    public static void main(String[] args) throws JSONException, IOException     {        ObjectMapper mapper = new ObjectMapper();        String key = "key1"; //whatever        JSONObject jo = new JSONObject("{key1:\"val1\", key2:\"val2\"}");        //Read from file        JSONObject root = mapper.readValue(new File("json_file"), JSONObject.class);        String val_newer = jo.getString(key);        String val_older = root.getString(key);        //Compare values        if(!val_newer.equals(val_older))        {          //Update value in object           root.put(key,val_newer);           //Write into the file            try (FileWriter file = new FileWriter("json_file"))             {                file.write(root.toString());                System.out.println("Successfully updated json object to file...!!");            }        }    }}