Java继承内存布局

public class Person {
    public int age;

    public void smile() {
        System.out.println("Person_smile()_age_" + age);
    }
}

class Student extends Person {
    public double score;

    public void study() {
        System.out.println("Student_study()_score_" + score);
    }
}

class MainTest {
    public static void main(String[] args) {
        Student s = new Student();
        s.score = 95.5;
        s.age = 8;
        // Person_smile()_age_8
        s.smile();
        // Student_study()_score_95.5
        s.study();

        Person p = new Person();
        p.age = 15;
        // Person_smile()_age_15
        p.smile();
    }
}