スレッドの停止の仕方について

public class StoppableThread extends Thread {

   private boolean stopRequested = false;   



   public void run(){

      boolean done = false;



       while(!stopRequested() && !done){

          ... // 必要な処理を行う

       }

   }

   public synchronized void requestStop(){

      stopRequested = true;

   }

   private synchronized boolean stopRequested(){

      return stopRequested;

   }

}

import java.lang.*;

public class ThreadSample 
{
  CMyThread t;
  ThreadSample(){
    t = null;
  }
  public void ThreadOnOff(boolean sw){
    if( sw == true ){
      if( t != null ) ThreadOnOff( false );
      t = new CMyThread((int)(Math.random() * 1000.0));
      t.start();
    }
    else {
      synchronized(t) {
        t.kill();
        t = null;
      }
    }
  }
  class CMyThread extends Thread
  {
    private boolean bThreadAlive;
    private long lngRandom;
    private int id;
    CMyThread(int id){
      this.id = id;
      bThreadAlive = true;
      lngRandom = (long)(Math.random() * 100.0);
    }
    public void kill(){
      bThreadAlive = false;
    }
    public void run(){
      while( bThreadAlive == true ){
        try{
          System.out.print(Long.toString(lngRandom) + "(" + Integer.toString(this.id) + ")," );
          sleep(350);
         }
        catch(InterruptedException ie){
        }
      }
      System.out.print(Long.toString(lngRandom) + "(" + Integer.toString(this.id) + ")," );
      System.out.println(" END");
    }
  }
  public static void main(String [] argv){
    ThreadSample app = new ThreadSample();
    try {
      app.ThreadOnOff(true);
      Thread.sleep(1020);
      app.ThreadOnOff(false);
      app.ThreadOnOff(true);
      Thread.sleep(520);
      app.ThreadOnOff(false);
      app = null;
     }
    catch( InterruptedException ie ){
    }
  }
}