code: public static boolean isRssEnabled(ServletContext servletContext) {
  		// Note: no locking performed since it's ok for two threads to do the work concurrently at first
  		Boolean isRssEnabled = (Boolean)servletContext.getAttribute(ISS_RSS_ENABLED_CACHE_KEY);
  		if(isRssEnabled == null) {
  			try {
  				Class.forName(RSS_SERVLET_CLASSNAME);
  				isRssEnabled = true;
  			} catch(ClassNotFoundException e) {
  				isRssEnabled = false;
  			}
  			servletContext.setAttribute(ISS_RSS_ENABLED_CACHE_KEY, isRssEnabled);
  		}
  		return isRssEnabled;
  	}
docs: Checks if the RSS module is installed.  This is done by checking for the existence of the
  servlet class.  This is cached in application scope to avoid throwing and catching ClassNotFoundException
  repeatedly.