java多线程问题(50分)

我根据书上的例子写了一个程序，无法编译，请有识之士指教一二。
public class Thread02
{
public static void main(String[] args)
{
Thread myThreadA=new Thread(new MyThread(),"threadA");
Thread myThreadB=new Thread(new MyThread(),"threadB");
myThreadA.start();
myThreadB.start();
try
{
Thread.currentThread().sleep(1000);
}
catch(InterruptedException e)
{
}
System.out.println(Thread.currentThread());
}
classdo
Noting
{
}
class MyThread extendsdo
Noting implements Runnable
{
public void run()
{
for(int cnt=0;cnt<5;cnt++)
{
System.out.println(Thread.currentThread()+"的运行次数:"+cnt);
try
{
Thread.currentThread().sleep((int)(Math.random()*100));
}
catch(InterruptedException e)
{
}
}
}
}
}

参考一下这个：
package nettest;
public class threadtest
{
public threadtest()
{
Thread myThreadA=new Thread(new MyThread(),"threadA");
Thread myThreadB=new Thread(new MyThread(),"threadB");
myThreadA.start();
myThreadB.start();
try
{
Thread.currentThread().sleep(1000);
}
catch(InterruptedException e)
{
}
System.out.println(Thread.currentThread());
}
public static void main(String args[]) {
threadtest t = new threadtest();
}
classdo
Noting
{
}
class MyThread extendsdo
Noting implements Runnable
{
public void run()
{
for(int cnt=0;cnt<5;cnt++)
{
System.out.println(Thread.currentThread()+"的运行次数:"+cnt);
try
{
Thread.currentThread().sleep((int)(Math.random()*100));
}
catch(InterruptedException e)
{
}
}
}
}
}
可以运行的

接受答案了，谢谢！