public class Database { 
 //... 

 public void displayContents(){ 
  for(Item i : items){ 
  System.out.println(i.getTitle()); 
  System.out.println("Play Time: "+i.getPlayTime()); 
  System.out.println("Owned? "+i.isOwned()); 
 }
} 

 public static void main(String[] args){ 
  Database d = new Database(); 
  d.addItem(new Album(...)); 
  d.addItem(new Video(...));
  d.displayContents(); 
 } 
}