title: request.getRemoteUser() sometimes returns null
body: <p>I have a java-web-application using struts2 combined with old-style servlets.
  Using Acegi security.</p>
  
  <p>In my servlets, I'm logging what the user is trying to do and which user it is. To get the user im using <code>request.getRemoteUser()</code></p>
  
  <p>But to my big supprise, the result is not consistent. Most of the times the <code>getRemoteUser()</code> returns the correct username, but every once in a while i get a null-value.</p>
  
  <p>What could be the reason behind this?</p>
  
  <p>EDIT:
  After your feedback i have figured out that the servlet-urls are not covered by security at all. So that could cause <code>getRemoteUser()</code>to be null. I will now implement security for these and do some more testing before i post back the results.</p>