求大侠帮忙看下这个程序,/,该如何解决_J2SE

求大侠帮忙看下这个程序,???/
求大虾帮忙改下，谢谢谢了！！！！[b][/b]1package patice;

import java.util.Scanner;

public class UI {

protected char[] message;

public void printMessage(String message){
System.out.println(this.message);

}
public String readMessage(){
Scanner sc=new Scanner(System.in);
String s = sc.nextLine();
return s;
}
}

package patice;

class UserLoginUI extends UI{
String user=new String("user");
String pass=new String("pass");
UserLoginUI st;

void login(){
System.out.println("请输入用户名和密码：");
if(user.equals(st.readMessage())){
System.out.println("登陆成功");
}else{
System.out.println("登陆失败");
}
}
}

package patice;

class AdminLoginUI extends UI{
String Admin=new String("user");
String pass=new String("pass");
AdminLoginUI st;

void login(){
System.out.println("请输入用户名和密码：");

if(Admin.equals(st.readMessage())){
System.out.println("登陆成功");
}else{
System.out.println("登陆失败");
}
}
}

package patice;

public class TestMain {

public static void main(String[] args){
UserLoginUI user1 = null;
user1.login();
AdminLoginUI admin=null;
admin.login();
}

}

------解决方案--------------------

Java code

import java.util.Scanner;public class UI {  protected char[] message;public void printMessage(String message){  System.out.println(this.message); }public String readMessage(){Scanner sc=new Scanner(System.in);String s = sc.nextLine();return s;}} class UserLoginUI extends UI{String user=new String("user");String pass=new String("pass");UserLoginUI st;void login(){System.out.println("请输入用户名和密码：");if(user.equals(st.readMessage())){System.out.println("登陆成功");}else{System.out.println("登陆失败");  } }}class AdminLoginUI extends UI{String Admin=new String("user");String pass=new String("pass");AdminLoginUI st;void login(){System.out.println("请输入用户名和密码："); if(Admin.equals(st.readMessage())){System.out.println("登陆成功");}else{System.out.println("登陆失败");  } }}class TestMain {public static void main(String[] args){UserLoginUI user1 = new UserLoginUI();user1.login();AdminLoginUI admin=new AdminLoginUI();admin.login();}}
------解决方案--------------------
下面是帮你改的程序，一般用户是user user登陆，管理员是admin admin登陆
UI类没有改，改了UserLoginUI和AdminLoginUI 还有测试类

对应package你改成自己的包就可以了
Java codepublic class UserLoginUI extends UI{    String user=new String("user");    String pass=new String("pass");//    UserLoginUI st;    public void login(){        System.out.println("请输入用户名");        String inputUser=this.readMessage();        System.out.println("请输入密码");        String password=this.readMessage();        if(user.equals(inputUser)&&pass.equals(password)){            System.out.println("登陆成功");        }else{            System.out.println("登陆失败");        }    }}