java小知识2(接口)

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();

}
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接口:
public interface Swim {
    public abstract void swim();

}
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未用到接口的类
public class rabbits extends Animal {
    public rabbits() {
    }
    public rabbits(String name, int age) {
        super(name, age);
    }
    @Override
    public void eat() {
        System.out.println("兔子吃胡萝卜");
    }

}
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public class Dog extends Animal implements Swim{
    public Dog() {
    }
    public Dog(String name, int age) {
        super(name, age);
    }
    @Override
    public void eat() {
        System.out.println("狗吃骨头");
    }
    @Override
    public void swim() {
        System.out.println("狗刨");
    }

}
---------------------------------------------

public class Frog extends Animal implements Swim{
    public Frog() {
    }
    public Frog(String name, int age) {
        super(name, age);
    }
    @Override
    public void eat() {
        System.out.println("青蛙吃虫子");
    }
    @Override
    public void swim() {
        System.out.println("蛙泳");
    }
}