java.lang.IllegalThreadStateException

下面是一组上产上述错误原因的代码

public class Test1 {
    public static void main(String[] args) {
        Thread thread = new Demo();
        thread.start();
        thread.start();//这里删掉就不会报IllegalThreadStateException异常
    }
}

class Demo extends Thread{
    int x = 0;
    @Override
    public void run() {
        while(true){
            if(x>100){
                System.out.println(x++);
            }
        }
    }
}

java.lang.IllegalThreadStateException

原文：http://blog.51cto.com/13579086/2067261