下列代码编译和运行的结果是：( )
public static void main(String[] args) {
Runnable r = new Runnable() {
public void run() {
System.out.print("Cat");
}
};
Thread t = new Thread(r) {
public void run() {
System.out.print("Dog");
}
};
t.start();
}Cat
Dog
运行无输出
编译失败
new Thread(r) {...}是匿名类的写法，等于覆盖了r的run()方法
