继承extends

class Person{
    String name;
    int age;

    void eat(){
        System.out.println("吃饭");
    }

    void introduce(){
        System.out.println("我的名字是"+name+",我的年龄是"+age);
    }
}

class Student extends Person{

}

Student继承Person，测试：

class Test{
    public static void main(String args[]){
        Student student=new Student();
        student.name="张三";
        student.age=18;

        student.eat();
        student.introduce():
    }
}