本实例实现计算机专业和会计专业的学生成绩统计，首先创建哈伊尔课程基础类，然后分别用计算机专业类和会计专业列继承课程技术类，最后在main方法中分别调用。实现代码如下：

import java.util.Scanner;
public class ExtendsDemo1 {
public static void mian (String [] args){
    Scanner sc=new Scanner(System.in);
    System.out.println("请输入学生姓名：");
    String  name=sc.next();
    System.out.println("请选择学生专业：");
    System.out.println("1.会计");
    System.out.println("2.计算机");
    int choose=sc.nextInt();
    if(choose==1){//选择会计专业
        System.out.println("请输入数学成绩：");
        double maths=sc.nextDouble();
        System.out.println("请输入英语成绩：");
        double english=sc.nextDouble();
        System.out.println("请输入会计基础成绩：");
        double accountBase=sc.nextDouble();
        System.out.println("请输入会计英语成绩：");
        double accountEnglish=sc.nextDouble();
        Accounting account=new Accounting(name,"会计",maths,english,accountBase,accountEnglish);
        System.out.println("学生信息为：");
        System.out.println(account.toString());//调用accounting类中的toString()方法
    }
    else if(choose==2){//选择计算机专业
        System.out.println("请输入数学成绩：");
        double maths=sc.nextDouble();
        System.out.println("请输入英语成绩：");
        double english=sc.nextDouble();
        System.out.println("请输入数据库成绩：");
        double datebase=sc.nextDouble();
        System.out.println("请输入Java成绩：");
        double javaProgram=sc.nextDouble();
        Computer computer=new Computer(name,"计算机",maths,english,datebase,javaProgram);
        System.out.println("学生信息为：");
        System.out.println(computer.toString());//调用computer类中的toString()方法
    }
    else{
        System.out.priintln("专业输入错误！");
    }
}
}
//基础信息类
class BaseCourse{//构造函数
    private String name;//姓名
    private String major;//专业
    private double maths;//数学
    private double english;//英语
    public BaseCourse(String name,String major,double english){
        this.name=name;
        this.major=major;
        this.maths=naths;
        this.english=english;
    }
    public double getMaths(){
        return maths;
    }
    public void setMaths(double maths){
        this.maths=maths;
    }
    public void setEnglish(double english){
        this.english=english;
    }
    public String getName(){
        return name;
    }
    public void setName(String name){
        this.name=name;
    }
    public String getMajor(String name){
        return major;
    }
    public void setMajor(Stirng major){
        this.major=major;
    }
}
//计算机专业
class Computer extends BaseCourse{
    private double datebase;//数据库
    private double javaProgram;//java 编程
    public Computer(String name,String major,double maths,double english,double datebase,doouble javaProgram){
        super(name,major,maths,english);//调用父类的构造方法
        this.datebase=datebase;
        this.javaProgram=javaProgram;
    }
    public doublegetDatebase(){
        return datebase;
    }
    public void setDatebase(double datebase){
        this.database=database;
    }
    public void setJavaProgram(double javaProgram){
        this.javaProgram=javaProgram;
    }
    ///重写toString()方法，用于输出属性值的以及科目的总分
    public String toString(){
        return this.getName()+":"+this.getMajor()+":总分为："+(this.getMaths()+this.getEnglish()+this.getDatebase()+this.getJavaProgram());
    }
    //会计专业
    class Accounting extends BaseCourse{
        private doubleaccountEnglish;//会计英语
        public Accounting(String name,String major,double maths,double english,double accountBase,double accountEnglish){
            super(name,major,maths,english);//调用父类的构造方法
            this.accountBase=accountBase;
            this.accountEnglish=accountEnglish;
            
        }
        public double getAccountbase(){
            return accountBase;
        }
        
        public void setAccountbase(double accountBase){
            this.accountBase=accountBase;
        }
        public double getAccountEnglish(){
            return accountEnglish;
        }
        public void setAccountEnglish(double accountEnglish){
            this.accountEnglish=accountEnglish;
        }
        //重写toString()方法，用于输出属性值以及科目的总分
        publicString toString(){
            return this.getName()+":"+this.getMajor()+":总分为："+(this.getMaths()+this.getEnglish()+this.getAccountBase()+this.getAcocountEnglish());
            
        }
    }
}