public class Animal {

public int age=10;

public String color; 

    public void eat() {

System.out.println("动物会吃东西！");

}

    public Animal() {

    System.out.println("Animal类执行了！");

    age=20;

    }

}

public class Dog extends Animal {

public Dog() {

System.out.println("Dog被执行了！");

}

}

public class Initial {

public static void main(String[] args) {

// TODO Auto-generated method stub

  Dog dog=new Dog();

   dog.eat();    

}

}

输出结果是：

Dog被执行了！

动物会吃东西！