code: public InetSocketAddress serverAddress() {
          try {
              return serverSocketChannel == null ? serverAddress
                  : (InetSocketAddress) serverSocketChannel.getLocalAddress();
          } catch (IOException e) {
              return serverAddress;
          }
      }
docs: Returns the server address. Before starting, the address is the
  address set with {@link #setServerAddress(InetSocketAddress)}. After
  starting the address is obtained from the created socket.
  
  @return the serverAddress