How to auto-increment the property of a JSONObject in Java?

A JSONObject is an unordered collection of name/value pairs and parses text from a String to produce a map-like object. However, we can auto-increment the property of a JSONObject using the increment() method of JSONObject class. If there is no such property, create one with a value of 1. If there is such a property and if it is an Integer, Long, Double or Float then add one to it.

Syntax

public JSONObject increment(java.lang.String key) throws JSONException

Example

import org.json.JSONException;
import org.json.JSONObject;
public class IncrementJSONObjectTest {
   public static void main(String[] args) throws JSONException {
      JSONObject jsonObj = new JSONObject();
      jsonObj.put("year", 2019);
      jsonObj.put("age", 25);
      System.out.println(jsonObj.toString(3));
      jsonObj.increment("year").increment("age");
      System.out.println(jsonObj.toString(3));
      jsonObj.increment("year").increment("age");
      System.out.println(jsonObj.toString(3));
      jsonObj.increment("year").increment("age");
      System.out.println(jsonObj.toString(3));
   }
}

Output

{
 "year": 2019,
 "age": 25
}
{
 "year": 2020,
 "age": 26
}
{
 "year": 2021,
 "age": 27
}
{
 "year": 2022,
 "age": 28
}