不可能完成任务？Thread的超时自动终止

/**
     * Executes <code>task</code>. Waits for <code>timeout</code>
     * milliseconds for the task to end and returns. If the task does not return
     * in time, the thread is interrupted and an Exception is thrown.
     * The caller should override the Thread.interrupt() method to something that
     * quickly makes the thread die or use Thread.isInterrupted().
     * @param task The thread to execute
     * @param timeout The timeout in milliseconds. 0 means to wait forever.
     * @throws TimeoutException if the timeout passes and the thread does not return.
     */
    public static void execute(Thread task, long timeout) throws TimeoutException {
        task.start();
        try {
            task.join(timeout);
        } catch (InterruptedException e) {
            /* if somebody interrupts us he knows what he is doing */
        }
        if (task.isAlive()) {
            task.interrupt();
            throw new TimeoutException();
        }
    }

public class ThreadA extends Thread {
	
	private long startTime;

	public ThreadA(String name) {
		super(name);
	}

	public void run() {
		this.startTime = System.currentTimeMillis();
		int i = 0;
		while (i++<20) {
			try {
				this.sleep(100);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println(this.getName()+":"+i);
		}

		System.out.println(this.getName()+"已完成");

	}
}

public class Test {
    public static void main(String args[]) throws TimeoutException{
         ThreadA a = new ThreadA("a");
         Test.execute(a, 10);
    }
	
    public static void execute(Thread task, long timeout) throws TimeoutException {   
        task.start();   
        try {   
            task.join(timeout);   
        } catch (InterruptedException e) {   
            System.out.println("ddd");
        }   
        if (task.isAlive()) {   
            task.interrupt();   
            throw new TimeoutException();   
        }   
    }  
}

private void run(){
      try{
            启动一个Timer，定时报一个TimeOutException 
            费时很长的业务逻辑
      }catch(TimeOutException e)
      {
          System.out.println("超时了!");
      }finally{
          System.out.println("释放资源退出!");
      }
}

 public static void execute(Thread task, long timeout) throws TimeoutException {   
        task.start();   
        try {   
            task.join(timeout);   
        } catch (InterruptedException e) {   
            /* if somebody interrupts us he knows what he is doing */  
        }   
        if (task.isAlive()) {   
            task.interrupt();   
            throw new TimeoutException();   
        }   
    }