send data from servlet to jsp page

hello...am having challenges sending data processed in a servlet back to be displayed in a jsp page. Consider my two files guestbook.jsp and the sign servlet (http://pastebin.com/Tka1KPS9). After the user enters something in the textarea, it's processed and now i want to re-display it in the jsp page! How do i do that? thanks

//guestbook.jsp

<%@page import="com.google.appengine.api.users.UserServiceFactory"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Log in Page</title>

<%@ page import="com.google.appengine.api.users.User" %>
<%@ page import="com.google.appengine.api.users.UserService" %>
<%@ page import="com.google.appengine.api.users.UserServiceFactory" %>

</head>
<body>

<%
UserService userService = UserServiceFactory.getUserService();
User user = userService.getCurrentUser();
if(user != null){
	pageContext.setAttribute("user", user);

%>

<p> Hello, user! (You can
<a href="<%= userService.createLogoutURL(request.getRequestURI()) %>">sign out</a>.)</p>
<%
} else{
%>

<p> Hello!
<a href= "<%= userService.createLoginURL(request.getRequestURI()) %>" >Login</a>

</p>

<%} %>

//display content back here from the servlet! how do i do this?

<form action="/sign" method="post">
    <div><textarea name="content" rows="3" cols="60"></textarea></div>
    <div><input type="submit" value="Post Greeting" /></div>
 </form>


</body>
</html>

//SignGuestbookServlet.java also /sign servlet from the web.xml

package com.tp.main;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.logging.Logger;

import javax.servlet.http.*;

import com.google.appengine.api.users.User;
import com.google.appengine.api.users.UserService;
import com.google.appengine.api.users.UserServiceFactory;

public class SignGuestbookServlet extends HttpServlet {

	private static final Logger log = Logger.getLogger(SignGuestbookServlet.class.getName());

	public SignGuestbookServlet() {
		// TODO Auto-generated constructor stub
	}

	public void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws IOException {

		 UserService userService = UserServiceFactory.getUserService();
	     User user = userService.getCurrentUser();

	        String content = req.getParameter("content");
	        if (content == null) {
	            content = "(No greeting)";
	        }
	        if (user != null) {
	            log.info("Greeting posted by user " + user.getNickname() + ": " + content);
	        } else {
	            log.info("Greeting posted anonymously: " + content);
	        }
	        System.out.println("content posted is: "+ content);
	        //redirect to the guestbook page still
	        PrintWriter out = resp.getWriter();
	        out.println("What you just entered: "+ content);

	        resp.sendRedirect("/guestbook.jsp");


	}

}