JAVA：继承

子类直接拥有父类所有公共资源，无需重复编写。 私有、构造、静态资源 不可继承。 重写必须方法签名一致、权限不缩小。

public class Person {
public String name;
public int age;

public void sleep() {
System.out.println("人类需要睡觉");
}
}
public class Student extends Person {
public String school;

public void study() {
System.out.println("学生正在学习");
}
}
public class Test {
public static void main(String[] args) {
Student stu = new Student();
stu.name = "张三";
stu.age = 20;
stu.school = "吉首大学";
stu.sleep();

stu.study();
}
}