Is this the best way to do this?

Question

I have a Authentication servlet that checks username/password. I'm getting I have got this to work but every once and a while I get errors and it doesn't work.
import java.io.*;
import javax.servlet.*;
import java.beans.*;
import javax.servlet.http.*;
import java.sql.*;
import java.util.Vector;
public class DisplayData extends HttpServlet {
//declare needed variables
public DisplayData(
HttpServletRequest req,
HttpServletResponse res,
String uName,
String uPass)
throws ServletException, IOException, SQLException {
//run code that takes uName and uPass and validates and sends redirect
//this code works
if (errorCode != 0) {
SQLException sqlError = new SQLException("Database Connection Failure");
throw sqlError;
} catch (java.lang.ClassNotFoundException errEvent) {
errorCode = 1;
} catch (SQLException sqlError) {
errorCode = 2;
} finally {
dbDriver.close();
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
String uName = req.getParameter("txtUserName");// get user name
String uPass = req.getParameter("txtPass"); //get password
if (uName != null && uPass != null) {
try {
DisplayData displayData = new DisplayData(req, res, uName, uPass);
} catch (SQLException s) {
System.out.println(s.getMessage());
public void doPost(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
doGet(req, res);
I think my error is where I send the req and res parameters

Answer 1

I figured out my problemThats good then dont fix it :)
even though there is no call to this I am required to
have:
public DisplayData(){
Why is that?
There is a call to this when the servelet is first instanciated and an object is created for it.
tho' it may happen only once in the servlet's life cycle.
i think OOAD demads a default constructor..... i am not sure about this.