code: public InputStream getResourceAsStream (int siteId, String path)
          throws IOException
      {
  //          Log.info("Loading site resource [siteId=" + siteId +
  //                   ", path=" + path + "].");
  
          // synchronize on the lock to ensure that only one thread per site
          // is concurrently executing
          synchronized (getLock(siteId)) {
              SiteResourceBundle bundle = getBundle(siteId);
  
              // make sure the path has no leading slash
              if (path.startsWith("/")) {
                  path = path.substring(1);
              }
  
              // obtain our resource from the bundle
              return bundle.getResourceAsStream(path);
          }
      }
docs: Loads the specific resource, from the site-specific jar file if one
  exists and contains the specified resource. If no resource exists
  with that path, null will be returned.
  
  @param siteId the unique identifer for the site for which we are
  loading the resource.
  @param path the path to the desired resource.
  
  @return an input stream via which the resource can be read or null
  if no resource could be located with the specified path.
  
  @exception IOException thrown if an I/O error occurs while loading
  a resource.