— Scott McNealy, Sun Microsystems Chairman, President and ceo

chapter 16
import java.util.*;
import java.io.*;
public class Jukebox3 {
ArrayList songList = new ArrayList();
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);
} 
}
This still doesn’t 
explain why the sort method 
failed on an ArrayList of Songs 
but worked for an ArrayList of 
Strings...
Remember where we were...
This is where it breaks! It worked fine when 
passed in an ArrayList, but as soon as we 
tried to sort an ArrayList, it failed.
File Edit Window Help Bummer
%javac Jukebox3.java
Jukebox3.java:15: cannot find symbol
symbol : method sort(java.util.ArrayList)
location: class java.util.Collections
Collections.sort(songList);
^
1 error
sorting 
a Song

---

collections 
with 
generics
you are here
4
547
public static