Program freezes when a thread is run in another class.

Question

I have a class that extends Thread, and then I have a GUI that needs this thread.
The thread class looks like this:
public class ScoreboardCheck extends Thread
    private int clock;
    private boolean running;
    public ScoreboardCheck(int timeOnClock)
        super();
        this.clock = timeOnClock;
        running = false;
    public int getClock()
        return this.clock;
    public void toggleRunning()
        if (running == false)
            running = true;
        else
            running = false;
    public void run()
        while (Thread.currentThread() == this)
            if (running == true)
                try
                    Thread.sleep(1000);
                    clock--;
                catch(InterruptedException ie)
                    ie.printStackTrace();
}This is suppose to update the clock on the GUI. I instantiate the thread in the GUI class, and call start on it. This works fine, but whenever I call run, it freezes up....Either way it never does anything.
In the GUI class, how am I suppose to continously update the clock without this thing freezing up? I've tried implementing runnable in the GUI class, but that didn't work.

Answer 1

Thanks for the replies, guys.
When I call start it doesn't freeze. That's good. The only other problem I'm faced with, is updating the GUI probably every second. I've tried using a run method in the GUI which runs while true, but that froze things up....This is the point I'm stuck at. For now, I'm going to try what someone suggested: the Timer class. Is there another way of doing this though? Without the timer?