Java Print JSONObject in Multiple lines

Question

When I run the "Write JSON to a file" code from this link, the entire JSON object is printed to a single line in the file. How do I print a JSONObject so that it is displayed nicely in multiple lines?

This is the output I get:

{"firstName":"John","lastName":"Smith","address":{"streetAddress":"21 2nd Street","city":"New York","state":"NY","postalCode":10021},"age":25,"phoneNumbers":[{"type":"home","number":"212 555-1234"},{"type":"fax","number":"212 555-1234"}]}

The code is shown below:

// Java program for write JSON to a file 

import java.io.FileNotFoundException; 
import java.io.PrintWriter; 
import java.util.LinkedHashMap; 
import java.util.Map; 
import org.json.simple.JSONArray; 
import org.json.simple.JSONObject; 

public class JSONWriteExample 
{ 
    public static void main(String[] args) throws FileNotFoundException 
    { 
        // creating JSONObject 
        JSONObject jo = new JSONObject(); 

        // putting data to JSONObject 
        jo.put("firstName", "John"); 
        jo.put("lastName", "Smith"); 
        jo.put("age", 25); 

        // for address data, first create LinkedHashMap 
        Map m = new LinkedHashMap(4); 
        m.put("streetAddress", "21 2nd Street"); 
        m.put("city", "New York"); 
        m.put("state", "NY"); 
        m.put("postalCode", 10021); 

        // putting address to JSONObject 
        jo.put("address", m); 

        // for phone numbers, first create JSONArray 
        JSONArray ja = new JSONArray(); 

        m = new LinkedHashMap(2); 
        m.put("type", "home"); 
        m.put("number", "212 555-1234"); 

        // adding map to list 
        ja.add(m); 

        m = new LinkedHashMap(2); 
        m.put("type", "fax"); 
        m.put("number", "212 555-1234"); 

        // adding map to list 
        ja.add(m); 

        // putting phoneNumbers to JSONObject 
        jo.put("phoneNumbers", ja); 

        // writing JSON to file:"JSONExample.json" in cwd 
        PrintWriter pw = new PrintWriter("JSONExample.json"); 
        pw.write(jo.toJSONString()); 

        pw.flush(); 
        pw.close(); 
    } 
}