this code is not working! please help me to find error. thanks.

<%@ page import="java.sql.*" %>
<%
Connection con=null;

String user=request.getParameter("userid");
session.putValue("userid",user); 
String pwd=request.getParameter("pwd");
try{
 Class.forName("sun.jdbc.odbc.JdbcOdbcDriver").newInstance();
     con = DriverManager.getConnection("jdbc:odbc:mydb","",""); 
       Statement st=con.createStatement();
       ResultSet rs=st.executeQuery("select * from table1 where userid='"+user+"' and pwd='"+pwd+"'");
       int i=0;
       while(rs.next()){
       i++;
       }
      if(i>0){
       out.println("welcome " +user);

       }
      else{
       response.sendRedirect("login.html");
      }
    }
    catch(Exception e){
    System.out.println(e);
}
%>