Thread: how to use jsp / servlet

I need help making proper way to make website using jsp/servlet.

file path: WebContent > login.jsp

       <form method="post" action="servlet">
          what's your username?<br /> <input type="text" name="usernameF" /><br />
          what's your password?<br /> <input type="password" name="passwordF" /><br />
	  <input type="submit" name="submitB" value="login" />
       </form>

file path: Java Resources > src > servlet.java

...
protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("text/html"); // useing html
 
		PrintWriter out = response.getWriter(); // write to browser
		HttpSession session = request.getSession(true);
 
		if (request.getParameter("submitB") != null) {
			if (usernameR.equals("")) {
				out.print("Error enter name");
			} else if (passwordR.equals("")) {
				out.print("Error enter password");
			} else {
				session.setAttribute("username", usernameR);
				response.sendRedirect(login.jsp);
			}
                }
}
...

Question 1: is this the proper way of using jsp/servlet?
Question 2: when user hit submit button in html form than it will run java code. but in servlet.java class the error will never print on login.jsp. how can i print errors on login.jsp? by error i mean:
out.print("Error enter name");
out.print("Error enter password");

p.s i look tutorial online but they only use jsp which is not good coding. if you have proper jsp/servlet tutorial let me know.

Thank you so much