// 4. REST API using Jersey @Path("/api/users") public class UserResource

HttpSession session = req.getSession(); String username = req.getParameter("username"); String password = req.getParameter("password"); if (authenticate(username, password)) session.setAttribute("user", username); session.setMaxInactiveInterval(1800); // 30 minutes resp.sendRedirect("dashboard.jsp"); else resp.sendRedirect("login.html?error=true");

// 1. Simple Servlet @WebServlet("/hello") public class HelloServlet extends HttpServlet protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException resp.setContentType("text/html"); PrintWriter out = resp.getWriter(); out.println("<h1>Hello from Java Server!</h1>"); out.println("Time: " + new java.util.Date());

private boolean authenticate(String user, String pass) // Implement actual authentication logic return "admin".equals(user) && "secret".equals(pass);