Sound Help

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)

/**
 * Write a description of class Jukebox here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Jukebox extends World
{
    String song= null;
    /**
     * Constructor for objects of class Jukebox.
     * 
     */
    public Jukebox()
    {    
        // Create a new world with 600x400 cells with a cell size of 1x1 pixels.
        super(600, 400, 1); 
    }
    public void setSong(String filename)
    {
        if (song != null)
        {
            song.stop();
        }
        song = new GreenfootSound(filename);
        song.play();
    }
}