题目做一半无从下手了

一个学校电脑管理记录小程序做到一半无从下手了 而且有些错误不会改了  用的程序是NETBEAN6.5   希望懂的大大们帮我改一下 顺便提下该加的东西和建议  下面是整个程序  最后面是个关系图（可能有点错误）

题目要求很简单，就是管理一些电脑，记录那些用过电脑的人 以及使用时间，并保存起来，让后能查询这些record（增加删除的功能可有可无）

main.java
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package cms;

/**
*
* @author Administrator
*/
public class Main {
private static Object JOptionPane;

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args,int i) {
        // TODO code application logic here
        String usernameString = JOptionPane.showInputDialog("Enter name");
        String timeString = JOptionPane.showInputDialog("Enter time");
        String computerString = JOptionPane.showInputDialog("Enter ID");
        
        String[] list = new String[i];
        System.out.println(list[i]);
        }
String output="";
}

multimedia_computer.java
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package cms;

/**
*
* @author Administrator
*/
public class multimedia_computer {
private  String  built_inspeaker;
private  String  displaycard;
private  String  micphone;
private  String  webcam;

    public String getBuilt_inspeaker() {
        return built_inspeaker;
    }

    public void setBuilt_inspeaker(String built_inspeaker) {
        this.built_inspeaker = built_inspeaker;
    }

    public String getDisplaycard() {
        return displaycard;
    }

    public void setDisplaycard(String displaycard) {
        this.displaycard = displaycard;
    }

    public String getMicphone() {
        return micphone;
    }

    public void setMicphone(String micphone) {
        this.micphone = micphone;
    }

    public String getWebcam() {
        return webcam;
    }

    public void setWebcam(String webcam) {
        this.webcam = webcam;
    }
}



record.java
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package cms;

/**
*
* @author Administrator
*/
public class record {
private  int begintime;
private  int time;
private  int endtime;

    public int getBegintime() {
        return begintime;
    }

    public void setBegintime(int begintime) {
        this.begintime = begintime;
    }

    public int getTime() {
        return time;
    }

    public void setTime(int time) {
        this.time = time;
    }

    public int getEndtime() {
        return endtime;
    }

    public void setEndtime(int endtime) {
        this.endtime = endtime;
    }
}
   user.java
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package cms;

/**
*
* @author Administrator
*/
public class user {

  private  int  userId;
  private  String  username;
  private  int   userphone;

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public int getUserphone() {
        return userphone;
    }

    public void setUserphone(int userphone) {
        this.userphone = userphone;
    }
}



non_multimedia_computer
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package cms;

/**
*
* @author Administrator
*/
public class non_multimedia_computer {
private int computerId;
private int num;
public  non_multimedia_computer(){
        super ();
}   
        public int getComputerId() {
        return computerId;
    }

    public void setComputerId(int computerId) {
        this.computerId = computerId;
    }

    public int getNum() {
        return num;
    }

    public void setNum(int num) {
        this.num = num;
    }
}
class multimedia_computer extends  non_multimedia_computer{
    }
class non_multimedia_computer {
    public non_multimedia_computer(string name){
     System.out.println("name is");
    }
}

[[it] 本帖最后由 xrr123 于 2008-12-16 12:51 编辑 [/it]]
----------------解决方案--------------------------------------------------------
光贴一段代码上来，谁能看懂啊，注释一点没有
----------------解决方案--------------------------------------------------------
问问题最好先把要问的问题描述清楚
----------------解决方案--------------------------------------------------------