can't you use reverse() after sorting ?

http://www.processing.org/reference/reverse_.html

I don't see how it can work, since Collections.reverseOrder() rely on the natural order of your class, which isn't defined (but could be).
Note that SortHighScore, being a Comparator, doesn't need to extend HighScore.

Now, indeed, if your class has only one sort order, you can make it to extend Comparable, instead of using an external Comparator. Then your Collections.reverseOrder() can work.

Reversing the order of a comparison is just matter of negating the sign of the compare (or compareTo) return value.

I made some changes. I got only highscore class now and i decided to use arraylist. It is working perfect.

1. 
   
2. highscorelist = new ArrayList();  // Create an empty ArrayList
3.     String rows[] = loadStrings("scores.txt");
4.   for (int i = 0; i < rows.length; i ++ ) { // Initialize
5.     String[] pieces = split(rows[i], TAB);  
6.     highscorelist.add(new HighScore(parseInt(pieces[0]), pieces[1]));
7.   }
8.   Collections.sort(highscorelist, Collections.reverseOrder());
9. 
   

1. 
   
2. class HighScore implements Comparable {
3.   int score;
4.   String name;
5.  
6.   HighScore() {
7.   }
8.  
9.   HighScore(int tempscore, String tempname) {
10.     score = tempscore;
11.     name = tempname;
12.   }
13.  
14.   // Overriding the compareTo method
15.   int compareTo(Object o1) {
16.         if (this.score == ((HighScore) o1).score)
17.             return 0;
18.         else if ((this.score) > ((HighScore) o1).score)
19.             return 1;
20.         else
21.             return -1;
22.     }
23.  
24.  
25.   // display the high score daata
26.   void display(int x, int y, int gapX){
27.     text(score, x+gapX, y);
28.     text(name, x, y);
29.   }
30.  
31.  
32.   // set name and score
33.   void setNameScore(int no, String what){
34.     name = what;
35.     score = no;
36.   }
37.  
38.  
39. }