javaのwebタスクアプリケーション:タイミング実行タスク

public class TaskManager implements ServletContextListener {    
/**   
  *          
  */   
public static final long PERIOD_DAY = DateUtils.MILLIS_IN_DAY;    
/**   
  *           
  */   
public static final long PERIOD_WEEK = PERIOD_DAY * 7;    
/**   
  *       
  */   
public static final long NO_DELAY = 0;    
/**   
  *       
  */   
private Timer timer;    
/**   
  *  Web             
  */   
public void contextInitialized(ServletContextEvent event) {    
        //         
  timer = new Timer("      ",true);     
  //      ,  (4   )        
  timer.schedule(new BackUpTableTask(),NO_DELAY, PERIOD_WEEK * 4);    
//  timer.schedule(new BackUpTableTask(),NO_DELAY, 30000);    
}    
/**   
  *  Web            
  */   
public void contextDestroyed(ServletContextEvent event) {    
  timer.cancel(); //          
}    
}   

public class BackUpTableTask extends TimerTask {     
        private static Log log = LogFactory.getLog(BackUpTableTask.class);     
        private static boolean isRunning = false;     
       public void run() {     
                  if (!isRunning) {     
                              isRunning = true;     
                               log.debug("      ..."); //         
                                  //working  add what you want to do     
                              log.debug("      ..."); //         
                              isRunning = false;     
                    } else {     
                             log.debug("           ..."); //                
                    }     
       }     
}   

 <listener>   
  <listener-class>***.TaskManager</listener-class>   
  <description>        </description>   
 </listener>