Java中子类型参数的多态性

class Animal {
    public void eat() {
        System.out.println("Animal is eating");
    }
}

class Dog extends Animal {
    public void eat() {
        System.out.println("Dog is eating");
    }
    
    public void bark() {
        System.out.println("Dog is barking");
    }
}

class Cat extends Animal {
    public void eat() {
        System.out.println("Cat is eating");
    }
    
    public void meow() {
        System.out.println("Cat is meowing");
    }
}

class Main {
    public static void main(String[] args) {
        List<Animal> animals = new ArrayList<>();
        animals.add(new Dog());
        animals.add(new Cat());
        
        for (Animal animal : animals) {
            animal.eat();
            
            if (animal instanceof Dog) {
                Dog dog = (Dog) animal;
                dog.bark();
            } else if (animal instanceof Cat) {
                Cat cat = (Cat) animal;
                cat.meow();
            }
        }
    }
}