Java upcast范围解析问题

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");
    }
}

public class Main {
    public static void main(String[] args) {
        Animal animal = new Dog();
        animal.eat(); // 输出：Dog is eating
        animal.bark(); // 编译错误，Animal类中没有bark方法
    }
}

public class Main {
    public static void main(String[] args) {
        Animal animal = new Dog();
        animal.eat(); // 输出：Dog is eating
        
        if (animal instanceof Dog) {
            Dog dog = (Dog) animal;
            dog.bark(); // 输出：Dog is barking
        }
    }
}