I like to use PuTTY to sniff HTTP response headers: http://www.chiark.greenend.org.uk/~sgtatham/putty/
I learned how to use PuTTY to sniff HTTP request/response when I was reading the O'Reilly book for Struts. It is mentioned somewhere in the introductory chapters. If you install PuTTY then you can configure a session to hit your Tomcat server. Use the PuTTY GUI to configure these settings for your session:
close window on exit: never
You can turn on logging if you want.
Type your HTTP request into a textpad and copy it to get it into your buffer so you can quickly paste it when you open a connection to your server. Something like this:
GET /Beer-v1/form.html HTTP/1.1
User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac )S X Mach-O; en-US; rv1.4) Gecko/20030624 Netscape/7.1
Hit the "Open" button on the PuTTY gui to open a connection to your web server.
Paste your request into the window that pops up by right-clicking the mouse
and then hit return a few times (you need a blank line to end the request, I think).
If you set PuTTY to "close window on exit = never" then you will see the HTTP response in the window:
HTTP/1.1 200 OK
Last-Modified: Sat, 13 Nov 2004 23:05:27 GMT
Date: Sun, 21 Nov 2004 22:37:40 GMT
<h1 align="center">Beer Selection Page</h1>
<form method="post" action="SelectBeer.do">
Select beer characteristics<p>
<select name="color" size="1">