Problem in Inserting in Database Using Jsp

<%@page import="com.dryclean.web.controller.DBUtil"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.Statement"%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.Connection"%>

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<%
/*AdduserBeans addCust_obj=new AdduserBeans();
addCust_obj.setCustomer_fname(request.getParameter("add_customer_fname"));
addCust_obj.setCustomer_lname(request.getParameter("add_customer_lname"));
addCust_obj.setCustomer_address(request.getParameter("add_customer_cellnumber"));
addCust_obj.setCustomer_cellnumber(request.getParameter("add_customer_address"));
*/
//DBUtil.SaveCustomer(addCust_obj);
//System.out.println(adduser.getCustomer_fname());
/*String dbUrl = "jdbc:mysql://localhost:3306/";
String db = "dry_cleaner";
String driver = "com.mysql.jdbc.Driver";
String user = "root";
String pass = "";*/
Connection con =null;
Statement stmt = null;
int updateQuery=0;
String query="INSERT INTO customers (customer_id, first_name,last_name,contact,address) VALUES('null','"+request.getParameter("add_customer_fname")+"','"+request.getParameter("add_customer_lname")+"','"+request.getParameter("add_customer_cellnumber")+"','"+request.getParameter("add_customer_address")+"')";
try{
	con = DBUtil.getConnection("jdbc:mysql://localhost:3306/","dry_cleaner","com.mysql.jdbc.Driver","root","");
	//Class.forName(driver);
	//con = DriverManager.getConnection (dbUrl+db,user,pass);
	System.out.println("connection success fully");
}catch(Exception ex){
	System.out.println("Connection error");
	}
try{
	updateQuery=stmt.executeUpdate(query);
	  if (updateQuery != 0) {
		  System.out.println("table is created successfully and " + updateQuery + " row is inserted.");
	  }
	//stmt = con.createStatement();
	//stmt.executeUpdate(query);
	/*
	 QueryString = "INSERT INTO user_master1(User_Name,UserId,User_Pwd)
 VALUES ('Mahendra',"+ "'mahendra25','1213456')";
  updateQuery = statement.executeUpdate(QueryString);
  if (updateQuery != 0) {
  System.out.println("table is created successfully and " + updateQuery
 + " row is inserted.");
	*/
	 /*if(stmt.executeUpdate(query)>0){
		   System.out.print("Records inserted");
		  }else{
		   System.out.print("insertion faild");
		  }*/
}catch(Exception ex){
	System.out.println("Query :"+query);
	//throw new Exception("Query Error");
}
response.sendRedirect("user_page.jsp");
%>