通过实现Rmmable接口创建线程，请在下面横线处填写代码完成此程序。
public class ThreadTest
{
public static void main(String args [])
{
Thread testObj1 = new Thread (new Hello ());
Thread testObj2 = new Thread (new Hello ());
testObj 2.start ( );
}
}
class Hello implements Runnable
{
int j;
public void run()
{
System.out.println("Hello" + j ++);
}
}