database login update problem

good day everybody, i want to used this code for users login but each time i want the count column to update, it will return an empty page. I know may be i did not structure
this code properly especially

below is the main code

<%@ page import="java.sql.*" %> 
<%@ page import="java.io.*" %> 
<html> 
<head> 
    <title>login</title>
</head> 
<body>
<%  
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
String username = request.getParameter("username");
String password = request.getParameter("password");
int count=0;

try{

Class.forName("com.mysql.jdbc.Driver").newInstance();

Connection con=null;
ResultSet rst=null;
Statement stmt=null;

con=DriverManager.getConnection("jdbc:mysql://localhost:3306/vat", "root", "root");

stmt=con.createStatement();
String query = "select count from vat where username='"+username+"' and password='"+password+"'";
System.out.println(query);
ResultSet rs = stmt.executeQuery(query);
while(rs.next()){
//count=rs.getInt(1);
}
if(count > 1){
pw.println("<font color=green size=5>you cannot login again</font>");
}
else{
String query1="UPDATE vata SET count = count + 1 WHERE username='"+username+"'";
 int i = stmt.executeUpdate(query1);		
pw.println("<font color=red size=5>welcome friend</font>");
}
}

catch(Exception e){
System.out.println(e.getMessage());
}

%>

thank u

Step 1: move the Java code out of a JSP and into a servlet or bean. There should be no Java code in a modern JSP.