帮我看看怎么回事的错误

错误出现了很长时间 显示是空指针错误，驱动也验证过了可以连接数据库。

异常报告

 datebase.java源代码

#database
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/bookstore-schema
username=root
password=123456789

package com.hkd.dao;

import java.sql.*;

public class Database {
	static String driver;
	static String url;
	static String username;
    static String password;    
    Connection conn=null;
    Statement sm=null;
    ResultSet rs=null;  
    
   
    
    public Connection getConn() {
		return conn;
	}

	public void setConn(Connection conn) {
		this.conn = conn;
	}

	public Database()
    {
    	GetProperty.getFile("database.properties");
    	driver=GetProperty.getValue("driver");
    	url=GetProperty.getValue("url");
    	username=GetProperty.getValue("username");
    	password=GetProperty.getValue("password");
    	
    	try {
			Class.forName(driver);
			conn=DriverManager.getConnection(url,username,password);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    	
    }
    
    public ResultSet getResult(String sql)
    {
    	try {
			sm=conn.createStatement();
			
			rs=sm.executeQuery(sql);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    	
    	return rs;
    	
    }
    
    public void myUpdate(String sql) throws SQLException 
    {
    	
			sm=conn.createStatement();
			sm.executeUpdate(sql);
		
    }
    
    public void close()
    {
    	try {
			if(rs!=null)
				rs.close();
			if(sm!=null)
				sm.close();
			if(conn!=null)
				conn.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    }
    

}

jsp源代码

<%@ page language="java" pageEncoding="utf-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core"  prefix="c" %>
<%@ page import="com.hkd.service.CategoryServiceImp" %>
<%@ page import="java.util.ArrayList" %>
<%@ page import="com.hkd.entity.Category" %>
    







.a{
 border-collapse: collapse; 
}

#contrainer{margin:0 auto;width:900Px;}
#header{height:100px;margin-bottom:5px; background-color:#2d6eba}
#center{height:800px; margin-bottom:5px; background-color:#dadbe3}
#footer{height:80px; background-color:#2d6eba}

.red{font-size:10px; color:#F00;}
.green{font-size:10px; color:#0C6}


<%CategoryServiceImp csi=new CategoryServiceImp(); 
  ArrayList clist=csi.checkcategory();
  session.setAttribute("catelist", clist); 
 %>







<%@ include file="header.jsp" %>  



 
  
  
 

 

 
User Information
 
 
User id:

 
New password:

 
Repeat password:

 
 
Account Information
 
 
First name:

 
Last name:

 
Email:

 
Phone:

 
Address1:

 
Address2:

 
City:

 
State:

 
Zip:

 
Country:

 
 
 
Profile Information
 
 

 
Language Proference:
 
chinesejapaneseenglish
 
 
Favourite Category:
 

 
 ${category.name} 
 
 
 Enable MyList
 
 Enable MyBanner

 
 
 

 
 
 
 
 
 
 
 
  
  
  


<%@ include file="footer.jsp" %>