public class Album extends Item { 

 private String artist;
 private int numTracks; 

 public Album(String title, String artist, int numTracks, double playTime, boolean ownIt, String comment) { 
  super(title, playTime, ownIt, comment); 

  this.artist = artist; 
  this.numTracks = numTracks; 
 } 

 //... 
}