Java类的继承，该怎么按要求更改？

import java.util.Scanner;

/**

 * @author niyite

 *

 */
/**

 *

 * 要求： (2) 对Employee模块进行扩展：派生manager类，manager具有职务、管理部门、职责等特性。

 * (3）对Route线路管理模块进行扩展：Route类派生出一个Local类和LongDistance类，Local类负责市内或近郊线路；

 * LongDistance类负责长途客运。自行设计两个子类属性和相关操作。这两个类里都有一个Bus类对象作为数据成员，

 * 用于记录运行于这两种公交线路的所有Bus信息。 （4） 定义测试类以继承的方式实现以上模块。

 *

 */
public class Test {
    public static void main(String args[]) {
        Scanner scn = new Scanner(System.in);
        System.out.println("请选择功能");
        int t = 6, i, m, n;
        //
        Bus bus[] = new Bus[2];
        Route route[] = new Route[2];
        Employee employee[] = new Employee[2];
        Passenger passenger[] = new Passenger[2];
        //
        for (i = 0; i <= 1; i++) {
            bus[i] = new Bus();
            route[i] = new Route();
            employee[i] = new Employee();
            passenger[i] = new Passenger();
        }
        //
        while (t != 0) {
            System.out.println("1.车辆管理");
            System.out.println("2.线路管理");
            System.out.println("3.员工管理");
            System.out.println("4.乘客管理");
            System.out.println("5.输出信息");
            t = scn.nextInt();
            //
            switch (t) {
            //
            case 1: {
                System.out.println("1.添加");
                System.out.println("2.修改");
                System.out.println("3.删除");
                m = scn.nextInt();
                switch (m) {//
                case 1: {
                    for (i = 0; i <= 1; i++)
                        if (bus[i].type == null)
                            break;
                    if (i != 2)
                        bus[i].Scn();
                    else
                        System.out.println("信息已满");
                }
                    break;
                // 添加车辆信息
                case 2: {
                    n = scn.nextInt();
                    if (bus[n - 1].type == null)
                        System.out.println("所选对象为空");
                    else
                        bus[n - 1].Scn();
                }
                    break;
                // 修改车辆信息
                case 3: {
                    n = scn.nextInt();
                    bus[n - 1].del();
                }
                    break;
                }
                // 删除车辆信息
            }
                break;
            // 车辆管理
            case 2: {
                System.out.println("1.添加");
                System.out.println("2.修改");
                System.out.println("3.删除");
                m = scn.nextInt();
                switch (m) {//
                case 1: {
                    for (i = 0; i <= 1; i++)
                        if (route[i].station == null)
                            break;
                    if (i != 2)
                        route[i].Scn();
                    else
                        System.out.println("信息已满");
                }
                    break;
                // 添加线路信息
                case 2: {
                    n = scn.nextInt();
                    if (route[n - 1].station == null)
                        System.out.println("所选对象为空");
                    else
                        route[n - 1].Scn();
                }
                    break;
                // 修改线路信息
                case 3: {
                    n = scn.nextInt();
                    route[n - 1].del();
                }
                    break;
                // 删除线路信息
                }
                break;
            }
            // 线路管理
            case 3: {
                System.out.println("1.添加");
                System.out.println("2.修改");
                System.out.println("3.删除");
                m = scn.nextInt();
                switch (m) {//
                case 1: {
                    for (i = 0; i <= 1; i++)
                        if (employee[i].name == null)
                            break;
                    if (i != 2)
                        employee[i].Scn();
                    else
                        System.out.println("信息已满");
                }
                    break;
                // 添加员工信息
                case 2: {
                    n = scn.nextInt();
                    if (employee[n - 1].name == null)
                        System.out.println("所选对象为空");
                    else
                        employee[n - 1].Scn();
                }
                    break;
                // 修改员工信息
                case 3: {
                    n = scn.nextInt();
                    employee[n - 1].del();
                }
                    break;
                // 删除员工信息
                }
                break;
            }
            // 员工管理
            case 4: {
                System.out.println("1.添加");
                System.out.println("2.修改");
                System.out.println("3.删除");
                m = scn.nextInt();
                switch (m) {//
                case 1: {
                    for (i = 0; i <= 1; i++)
                        if (passenger[i].name == null)
                            break;
                    if (i != 2)
                        passenger[i].Scn();
                    else
                        System.out.println("信息已满");
                }
                    break;
                // 添加乘客信息
                case 2: {
                    n = scn.nextInt();
                    if (passenger[n - 1].name == null)
                        System.out.println("所选对象为空");
                    else
                        passenger[n - 1].Scn();
                }
                    break;
                // 修改乘客信息
                case 3: {
                    n = scn.nextInt();
                    passenger[n - 1].del();
                }
                    break;
                // 删除乘客信息
                }
                break;
            }
            // 乘客管理
            case 5: {
                for (i = 0; i <= 1; i++) {
                    System.out.println("线路" + (i + 1));
                    bus[i].Prn();
                    route[i].Prn();
                    employee[i].Prn();
                    passenger[i].Prn();
                }
            }

            }
        }
    }
}

class Bus {
    Scanner scn = new Scanner(System.in);
    String type;
    int number;
    int route;
    int capacity;

    void Scn() {
        System.out.println("请依次输入车辆的线路类型，车号，线路号，载客量，以回车分隔");
        type = scn.nextLine();
        number = scn.nextInt();
        route = scn.nextInt();
        capacity = scn.nextInt();
    }

    void Prn() {
        System.out.println("线路类型:" + type);
        System.out.println("车号:" + number);
        System.out.println("线路号:" + route);
        System.out.println("载客量:" + capacity);
    }

    void del() {
        type = null;
        number = 0;
        route = 0;
        capacity = 0;
    }
}

class Local extends Route {

}

class Distance extends Route {

}

class Route {
    Scanner scn = new Scanner(System.in);
    int StopNo;
    String station;
    String destination;
    String RunTime;

    void Scn() {
        System.out.println("请依次输入线路的站数，始发站，终点站，运行时间，以回车分隔");
        StopNo = scn.nextInt();
        scn.nextLine();
        station = scn.nextLine();
        destination = scn.nextLine();
        RunTime = scn.nextLine();
    }

    void Prn() {
        System.out.println("站数:" + StopNo);
        System.out.println("始发站:" + station);
        System.out.println("终点站:" + destination);
        System.out.println("运行时间:" + RunTime);
    }

    void del() {
        StopNo = 0;
        station = null;
        destination = null;
        RunTime = null;
    }

}

class Employee {
    Scanner scn = new Scanner(System.in);
    String name;
    int ID;
    int age;
    double salary;
    String department;

    void Scn() {
        System.out.println("请依次输入员工的姓名，工号，年龄，工资，部门，以回车分隔");
        name = scn.nextLine();
        ID = scn.nextInt();
        age = scn.nextInt();
        salary = scn.nextDouble();
        scn.nextLine();
        department = scn.nextLine();
    }

    void Prn() {
        System.out.println("姓名:" + name);
        System.out.println("工号:" + ID);
        System.out.println("年龄:" + age);
        System.out.println("工资:" + salary);
        System.out.println("部门:" + department);
    }

    void del() {
        name = null;
        ID = 0;
        age = 0;
        salary = 0;
        department = null;
    }

}

class Manager extends Employee {
    String position, duty, manage;
}

class Passenger {
    Scanner scn = new Scanner(System.in);
    String name;
    String sex;
    int age;
    String message;

    void Scn() {
        System.out.println("请依次输入乘客的姓名，性别，年龄，信息，以回车分隔");
        name = scn.nextLine();
        sex = scn.nextLine();
        age = scn.nextInt();
        message = scn.nextLine();
    }

    void Prn() {
        System.out.println("姓名:" + name);
        System.out.println("性别:" + sex);
        System.out.println("年龄:" + age);
        System.out.println("信息:" + message);
    }

    void del() {
        name = null;
        sex = null;
        age = 0;
        message = null;
    }
}