SwingWorker thead does not stop after interrupt?

Question

Hi,
I am using SwingWorker class from Java Tutorial, in order to run a new task thread not in event thread. So I defined a class MyTask that extends SwingWorker, and implements construct() and finish() method (see below for SwingWorker class). Meanwhile, I use a run button to control the task run, that is, when user click the run button the new thread starts by calling MyTask.start(), but I also want to have a Cancel button to stop the task run.
SO in my actionPerformed() for cancel button, I use the following to stop the task, but the problem is that the task does not actually stop running! Any one knows what is the reason and solution? -- Thanks!
     public void cancel() {
          if (task != null) {
               task.interrupt();
          dispose();
     }ps: SwingWorker class from tutorial is also included here.
public abstract class SwingWorker {
    private Object value;  // see getValue(), setValue()
    private Thread thread;
     * Class to maintain reference to current worker thread
     * under separate synchronization control.
    private static class ThreadVar {
        private Thread thread;
        ThreadVar(Thread t) { thread = t; }
        synchronized Thread get() { return thread; }
        synchronized void clear() { thread = null; }
    private ThreadVar threadVar;
     * Get the value produced by the worker thread, or null if it
     * hasn't been constructed yet.
    protected synchronized Object getValue() {
        return value;
     * Set the value produced by worker thread
    private synchronized void setValue(Object x) {
        value = x;
     * Compute the value to be returned by the <code>get</code> method.
    public abstract Object construct();
     * Called on the event dispatching thread (not on the worker thread)
     * after the <code>construct</code> method has returned.
    public void finished() {
     * A new method that interrupts the worker thread.  Call this method
     * to force the worker to stop what it's doing.
    public void interrupt() {
        Thread t = threadVar.get();
        if (t != null) {
            t.interrupt();
        threadVar.clear();
     * Return the value created by the <code>construct</code> method. 
     * Returns null if either the constructing thread or the current
     * thread was interrupted before a value was produced.
     * @return the value created by the <code>construct</code> method
    public Object get() {
        while (true) { 
            Thread t = threadVar.get();
            if (t == null) {
                return getValue();
            try {
                t.join();
            catch (InterruptedException e) {
                Thread.currentThread().interrupt(); // propagate
                return null;
     * Start a thread that will call the <code>construct</code> method
     * and then exit.
    public SwingWorker() {
        final Runnable doFinished = new Runnable() {
           public void run() { finished(); }
        Runnable doConstruct = new Runnable() {
            public void run() {
                try {
                    setValue(construct());
                finally {
                    threadVar.clear();
                SwingUtilities.invokeLater(doFinished);
        Thread t = new Thread(doConstruct);
        threadVar = new ThreadVar(t);
     * Start the worker thread.
    public void start() {
        Thread t = threadVar.get();
        if (t != null) {
            t.start();
}

Answer 1

take a look to this sample.
http://java.sun.com/products/jfc/tsc/articles/threads/threads2.html