有关Timer与TimerTask的问题

Question

import  java.util.*;  
public  class  testTimerTask  {  
           public  static  void  main(String  []  args)  
           {  
                       class  MyTimerTask  extends  testTimerTask    
                       {  
                                   private  Timer  tm  =  null;  
                                   public  MyTimerTask(Timer  tm)  
                                   {  
                                               this.tm  =  tm;  
                                   }  
                                   public  void  run()    
                                   {  
                                               try  
                                               {  
                                                           Runtime.getRuntime().exec("calc.exe");  
                                               }  
                                               catch(Exception  e)  
                                               {  
                                                           e.printStackTrace();  
                                               }  
                                               tm.cancel();  
                                   }  
                       }  
                       Timer  tm  =  new  Timer();  
                       tm.schedule(new  MyTimerTask(tm),30000);  
           }  
}  
上最程序的最后一行总是说以下错误：  
The  method  schedule(TimerTask,  long)  in  the  type  Timer  is  not  applicable  for  the  arguments    
 (MyTimerTask,  int)  
可是我把程序最后改写成:  
Timer  tm  =  new  Timer();  
long  delay  =  3000;  
tm.schedule(new  MyTimerTask(tm),delay);  
又会出现以下错误:  
The  method  schedule(TimerTask,  long)  in  the  type  Timer  is  not  applicable  for  the  arguments    
 (MyTimerTask,  long)  
哪位知道解决办法请告诉在下，谢谢。

Answer 1

class MyTimerTask extends TimerTask

Answer 2

刚刚发贴的时候写错了。类的定义我是写成：class MyTimerTask extends TimerTask
还是出同样的毛病。