Refresher on what Override is for

//import package 
package com.teamtreehouse.model;

//new public class
public class Song {

     //private unexposed variables  - immutable variables.  Can only get values not set them.
     private String mArtist;
     private String mTitle;
     private String mVideoUrl;

    //use constructor to initiliae variables from member variables. 
    public Song(String artist, String title, String videoUrl) {
      mArtist = artist; 
      mTitle = title;
      mVideoUrl = videoUrl;

    }

    //expose variables with "getter functions"
    public String getTitle() {
       return mTitle;
    }

    public String getArtist() {
      return mArtist;
    }

    public String getVideoUrl() {
      return mVideoUrl;
    }


    //Override Bases toString method -prepare instance to be used as a String.  
    @Override
    public String toString() {
      return String.format("Song: %s by %s", mTitle, mArtist);
    }

}

package com.teamtreehouse.model;

import java.util.List;
import java.util.ArrayList;

public class SongBook {

    //a new private interface  List variable.
    private List<Song> mSongs;

    //constructor SongBook
    public SongBook() {
      mSongs = new ArrayList<Song>();

    }

    //public method, returns nothing. takes Song List as a parameter
    public void addSong(Song song) {
      mSongs.add(song);
    }

    //
    public int getSongCount() {
      return mSongs.size();
    }

}

//import packages since main file is outside the package. 
import com.teamtreehouse.model.Song;
import com.teamtreehouse.model.SongBook;

//new public class
public class Karaoke {

   //static method named nain that takes array of args returns nothing. 
   public static void main(String[] args) {

  //a new instance of a song from Song class
  Song song = new Song("Michael Jackson",
                       "Beat It",
                       "https://www.youtube.com/watch?v=SaEC9i9Q0vk");

   //a new instance of a songbook.  
   SongBook songBook = new SongBook();

   //write to console
   System.out.printf("Adding %s %n", song);
   songBook.addSong(song);
   System.out.printf("There are %d song(s). %n", songBook.getSongCount() );


   }
}