— Scott McNealy, Sun Microsystems Chairman, President and ceo

();
public static void main(String[] args) {
new Jukebox3().go();
}
public void 
go()
{ 
getSongs(); 
System.out.println(songList);
Collections.sort(songList);
System.out.println(songList); 
}
void 
getSongs()
{
try {
File file = new File(“SongList.txt”);
BufferedReader reader = new BufferedReader(new FileReader(file));
String line = null;
while ((line= reader.readLine()) != null) {
addSong(line);
}
} catch(Exception ex) {
ex.printStackTrace();
}
}
void 
addSong(String lineToParse)
{
String[] tokens = lineToParse.split(“/”);
 
 
Song nextSong = new Song(tokens[0], tokens[1], tokens[2], tokens[3]);
 
 
songList.add(nextSong);
} 
}
Change to an ArrayList of Song 
objects instead of String.
Create a new Song object using the four tokens 
(which means the four pieces of info in the song file 
for this line), then add the Song to the list.
Changing the Jukebox code to use Songs 
instead of Strings
Your code changes only a little—the file I/O code is the same, 
and the parsing is the same (String.split()), except this time 
there will be four tokens for each song/line, and all four will be 
used to create a new Song object. And of course the ArrayList 
will be of type instead of .

---

538
 
chapter 16
It won’t compile !
Something’s wrong... the Collections class clearly shows there’s a 
sort() method, that takes a List. 
ArrayList is-a List, because ArrayList implements the List interface, 
so... it should work. 
But it doesn’t!
The compiler says it can’t find a sort method that takes an 
ArrayList, so maybe it doesn’t like an ArrayList of Song 
objects? It didn’t mind an ArrayList, so what’s the 
important difference between Song and String? What’s the 
difference that’s making the compiler fail?
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