Cancel() method in "Timer" class

Question

Hi there,
I'm just a bit wondering what's the problem with the following code. if i comment out the t.cancel() method, the program will print out "OK!". but if i don't comment it out, the program will print out nothing, although it compiles perfectly. by the way, i can't tell the difference between putting t.cancel() there and putting it within "public void run()" and after that "system.out.println("OK!");" method. I think t.cancel() can be called in any place in the program.
any comments will be very much appreciated.
Eileen2
import java.util.*;
public class Thread1
     private Timer t;
     public Thread1()
          t = new Timer();
          t.schedule(new Task(), 4000);
//          t.schedule(new Task(), 2000);
          t.cancel();
     private class Task extends TimerTask
          public void run()
               System.out.println("OK!");
     public static void main(String[] args)
          System.out.println("This program is to test how threads work...");
          new Thread1();

Answer 1

What you describe is exactly what I would expect that would happen. By calling cancel() on the timer, you discard any scheduled tasks, so your Task.run() will never be executed and you will not see the "OK!". Note that the call to schedule() returns immediately. It doesn't wait until the task will execute.
Your question is not very clear. What do you want to know specifically about the behaviour of your program? What did you expect it to do and what is the difference between what it really does and what you expected?
Jesper