线程同步问题深度剖析

package cn.itcast.thread;

public class ThreadTest3 {
    public static void main(String[] args) {
         Runnable r=new HelloThread();
         Thread t1=new Thread(r);
         //r=new HelloThread();
         Thread t2=new Thread(r);
         t1.start();
         t2.start();
    }

}

class HelloThread implements Runnable
{
    int i; //成员变量
    @Override
    public void run() {
     int i=0; //局部变量
     while(true){
         System.out.println("number:"+this.i++); //调用的是成员变量i,此时无止境的执行下去
         try {
            Thread.sleep((long) (Math.random()*1000));
        } catch (InterruptedException e) {

            e.printStackTrace();
        }
        if(i==50){
            break;
        }
     }
    }
}