public abstract class Animal {

     private String name;

     private int age;

     public Animal() {

     }

     public Animal(String name, int age) {

         this.name = name;

         this.age = age;

     }

     public String getName() {

         return name;

     }

     public void setName(String name) {

         this.name = name;

     }

     public int getAge() {

         return age;

     }

     public void setAge(int age) {

         this.age = age;

     }

     public abstract void eat();

 }

 public class Cat extends Animal{

     public Cat() {

     }

     public Cat(String name, int age) {

         super(name, age);

     }

     @Override

     public void eat(){

         System.out.println("猫吃鱼!");

     }

 }

 public class Dog extends Animal{

     public Dog() {

     }

     public Dog(String name, int age) {

         super(name, age);

     }

     @Override

     public void eat(){

         System.out.println("狗吃骨头!");

     }

 }

 public class test {

     public static void main(String[] args) {

         //创建对象

         //无参

         Animal a1=new Cat();

         a1.setName("加菲");

         a1.setAge(5);

         Animal b1=new Dog();

         b1.setName("小黑");

         b1.setAge(6);

         //有参

         Animal a2=new Cat("加菲",5);

         Animal b2=new Dog("小黑",6);

         //输出

         a1.eat();

         a2.eat();

         b1.eat();

         b2.eat();

     }

 }