Thread的子类创建线程

public class Example8_3{
 public static void main(String arg[]){
  Left left=new Left();
  Right right=new Right();
  left.start();
  right.start();
  while(true){
   if(left.n==8||right.n==8)
   System.exit(0);
   
  }
 }
}
class Left extends Thread{
 int n=0;
 public void run(){
  while (true){
   n++;
   System.out.printf(" %s","我在左面写字");
                 try{  sleep((int)(Math.random()*100)+100);}
   catch(InterruptedException e){}
  }
 }
}
class Right extends Thread{
 int n=0;
 public void run(){
  while(true){
   n++;
   System.out.printf(" %40s","我在右面写字");
   try{ sleep((int)(Math.random()*100)+100);}
    catch(InterruptedException e){}
   
  }
 }
}