error-page target for error-code 404 is executed every time

[Dan Jacobs <dj...@modelobjects.com>]

I have been doing some performance tuning on my JPlates and Struts app,
and noticed that if I have the following mapping in my web.xml file,
that my error-handler is executed on every request, even though only the
correct page is displayed in the browser.  
 
No other error-codes or other error-page elements seem to have this odd
behavior.
 
  <error-page>
    <error-code>404</error-code>
    <location>/jplates.webadmin.ErrorPage.jplate</location>
  </error-page>
 
I added some debugging log-output to the JPlatesServlet and found that
the error-page target is executed *after* the intended JPlates class has
generated output.
 
Has anyone seen this kind of behavior before?  Is there a known cause?
 
-- Dan Jacobs
-- JPlates, Inc.
-- http://www.jplates.com