code: private boolean load(URL url) throws ClassNotFoundException, IOException, ZoneRulesException {
          boolean updated = false;
          if (loadedUrls.add(url.toExternalForm())) {
              InputStream in = null;
              try {
                  in = url.openStream();
                  updated |= load(in);
              } finally {
                  if (in != null) {
                      in.close();
                  }
              }
          }
          return updated;
      }
docs: Loads the rules from a URL, often in a jar file.
  
  @param url  the jar file to load, not null
  @return true if updated
  @throws ClassNotFoundException if a classpath error occurs
  @throws IOException if an IO error occurs
  @throws ZoneRulesException if the data is already loaded for the version