code: public String getServerName()
      {
          String host=_listener.getHost();
          if (InetAddrPort.__0_0_0_0.equals(host) &&
              _connection instanceof Socket)
              host = ((Socket)_connection).getLocalAddress().getHostName();
          
          return host;
      }
docs: Get the listeners HttpServer.
  But if the name is 0.0.0.0, then the real interface address is used.
  @return HttpServer.