Program:-

Index.html:-
<!DOCTYPE html>
<html>
    <head>
        <title>Experiment</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
    </head>
    <body>
        <form method="post" action="login"><br><br>
            Username:<input type="text" name="username"><br><br>
            Password:<input type="password" name="password"><br><br>
            <input type="submit" value="Login">

        </form>
     </body>
</html>


Web.xml:-
<web-app>
<servlet>>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>LoginClass</servlet-class>
    </servlet>
    
    <servlet-mapping>
                <servlet-name>LoginServlet</servlet-name>
                <url-pattern>/login</url-pattern>

    </servlet-mapping>
    
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
</web-app>


LoginClass.java:-

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class LoginClass extends HttpServlet {
    protected void doPost(HttpServletRequest request,HttpServletResponse response)
            throws ServletException, IOException
    {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        
        String result;
        
        try
        {
           String username = request.getParameter("username");
           
           String password = request.getParameter("password");
           
           if(username.equals("hanu")&& password.equals("hanu123")){
               result="Login Successful";
           }
           else{
               result="Authentication failure";
           }
           out.println("<h2>"+result+"</h2>");
               }
        finally
        {
            out.close();
        }
    }
}