code: private String getPort() {
          String url = getUrl();
          int i = url.indexOf("://") + 3;
          int j = url.indexOf("/", i);
          String s = i == 2 || j == -1 ? "" : url.substring(i, j);
          i = s.indexOf(":");
          return i == -1 ? "" : s.substring(i + 1);
      }
docs: Extract the TCP port from the connection URL.
  
  @return The TCP port, or empty string if none.