Create login form and perform state management using Cookies, HttpSession and URL Rewriting.

                                    <!-- XML FILE -->
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
    <servlet>
        <servlet-name>FirstServlet</servlet-name>
        <servlet-class>FirstServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>SecondServlet</servlet-name>
        <servlet-class>SecondServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>FirstServlet</servlet-name>
        <url-pattern>/FirstServlet</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>SecondServlet</servlet-name>
        <url-pattern>/SecondServlet</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>

</web-app>

                                    //First Servlet File
import java.io.*;
import javax.servlet.ServletException;
import javax.servlet.http.*;

public class FirstServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {
            response.setContentType("text/html");
            PrintWriter out = response.getWriter();
            String name = request.getParameter("userName");
            String pwd = request.getParameter("password");
            if (pwd.equals("birju") && name.equals("admin")) {
                out.print("<h1>Welcome " + name + "</h1>");
                Cookie ck = new Cookie("uname", name);// creating cookie object
                response.addCookie(ck);// adding cookie in the response
                out.print("<b>Cookie has been generated for this session<br></b>");
                out.print("<b>Click on button to view Cookie...</b>");
                // creating submit button
                out.print("<form action='SecondServlet' method='post'>");
                out.print("<br><input type='submit' value='go'>");
                out.print("</form>");
            } else {
                out.println("Incorrect Username or Password!!!");
            }
            out.close();
        } catch (Exception e) {
            System.out.println(e);
        }
    }

}

//Second Servlet File
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class SecondServlet extends HttpServlet {

    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {

            response.setContentType("text/html");
            PrintWriter out = response.getWriter();

            Cookie ck[] = request.getCookies();
            out.print("Value stored in Cookie : " + ck[0].getValue());

            out.close();

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

}