class Demo implements Runnable
{
    private int i = 10;
    public void fun()
    {
        System.out.println(Thread.currentThread().getName() + "在运行```");
    }
    public void run()
    {
        while(i-- > 0)
        {
            this.fun();
        }
    }
};
public class ThreadDemo1
{
    public static void main(String[] args)
    {
        Demo a = new Demo();
        Thread a1 = new Thread(a,"线程1");
        Thread a2 = new Thread(a,"线程2");
        Thread a3 = new Thread(a,"线程3");
        Thread a4 = new Thread(a,"线程4");
        a1.start();
        a2.start();
        a3.start();
        a4.start();
    }
}

为何会是乱码呢~

就是会出现好多行相同的不是中国字的中国字，他们说估计是源代码不是Unicode的。不过，还是不很清楚。