code: public static boolean shouldBodyBeZero(HttpServletRequest request, int responseStatus) {
  
  		//Check for NO_CONTENT
  		if (responseStatus == HttpServletResponse.SC_NO_CONTENT) {
  			if (log.isDebugEnabled()) {
  				log.debug("{} resulted in a {} response. Removing message body in accordance with RFC2616.",
  						request.getRequestURL(), HttpServletResponse.SC_NO_CONTENT);
  			}
  			return true;
  		}
  
  		//Check for NOT_MODIFIED
  		if (responseStatus == HttpServletResponse.SC_NOT_MODIFIED) {
  			if (log.isDebugEnabled()) {
  				log.debug("{} resulted in a {} response. Removing message body in accordance with RFC2616.",
  						request.getRequestURL(), HttpServletResponse.SC_NOT_MODIFIED);
  			}
  			return true;
  		}
  		return false;
  	}
docs: Performs a number of checks to ensure response saneness according to the rules of RFC2616:
  <ol>
  <li>If the response code is {@link javax.servlet.http.HttpServletResponse#SC_NO_CONTENT} then it is illegal for
  the body to contain anything. See http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.5
  <li>If the response code is {@link javax.servlet.http.HttpServletResponse#SC_NOT_MODIFIED} then it is illegal for
  the body to contain anything. See http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.5
  </ol>
  @param request the client HTTP request
  @param responseStatus the responseStatus
  @return true if the response should be 0, even if it is isn't.