Java set value at specific location of arraylist

/**
 * @author lautturi.com 
 * Java example: java modify the element at the specified position in array list 
 */

import java.util.*;

public class Lautturi {

	public static void main(String[] args) {

		ArrayList<String> arrList = new ArrayList<String>();
		arrList.add("lautturi");
		arrList.add("java");
		arrList.add("python");
		arrList.add("hello");
		arrList.add("js");

		System.out.println("Array List: "+ arrList);
        arrList.set(3, "PHP");
        System.out.println("Array List: "+ arrList);
	}
}

output:

Array List: [lautturi, java, python, hello, js]
Array List: [lautturi, java, python, PHP, js]