How to create Json Object using Object Model?

package com.javaapi.json.examples;

import java.io.StringWriter;

import javax.json.Json;
import javax.json.JsonObject;
import javax.json.JsonObjectBuilder;
import javax.json.JsonWriter;

public class CreateJsonObjEx {

	public static void main(String a[]){
		
		JsonObjectBuilder jsonBuilder = Json.createObjectBuilder();
		jsonBuilder.add("emp_name", "Nataraj G");
		jsonBuilder.add("emp_id", 1016);
		jsonBuilder.add("salary", 20000);
		
		JsonObject empObj = jsonBuilder.build();
		// here we are writing to String writer. 
		// if you want you can write it to a file as well
		StringWriter strWtr = new StringWriter();
        JsonWriter jsonWtr = Json.createWriter(strWtr);
        jsonWtr.writeObject(empObj);
        jsonWtr.close();
        
        System.out.println(strWtr.toString());
	}
}

{"emp_name":"Nataraj G","emp_id":1016,"salary":20000}