java/java

Animal.java:
public abstract class Animal {
    public abstract void makeSound();
}
Dog.java:
public class Dog extends Animal implements Swimmable {
    @Override
    public void makeSound() {
        System.out.println("汪汪汪！");
    }

    @Override
    public void swim() {
        System.out.println("狗在游泳！");
    }
}
Cat.java:
public class Cat extends Animal {
    @Override
    public void makeSound() {
        System.out.println("喵喵喵！");
    }
}
Main.java:
public class Main {
    public static void main(String[] args) {
        // 多态调用
        Animal dog = new Dog();
        Animal cat = new Cat();

        System.out.println("狗的叫声：");
        dog.makeSound();

        System.out.println("猫的叫声：");
        cat.makeSound();

        // 测试游泳功能
        if (dog instanceof Swimmable) {
            ((Swimmable) dog).swim();
        }

        if (cat instanceof Swimmable) {
            ((Swimmable) cat).swim();
        } else {
            System.out.println("猫不会游泳！");
        }
    }
}