package Demo4;
public class Animal {
}package Demo4;
public class Cat extends Animal {
}package Demo4;
public class Dog extends Animal {
}package Demo4;
public class AnimalApp {
public static void main(String[] args) {
Animal a = new Dog();
Animal b = new Cat();
Dog c = (Dog) a;
Cat d = (Cat) b;
Dog e = (Dog) b; // 형 변환 예외 발생
}
}