code: public void open() throws TTransportException {
      if (isOpen()) {
        throw new TTransportException(TTransportException.ALREADY_OPEN, "Socket already connected.");
      }
  
      if (host.length() == 0) {
        throw new TTransportException(TTransportException.NOT_OPEN, "Cannot open null host.");
      }
      if (port <= 0) {
        throw new TTransportException(TTransportException.NOT_OPEN, "Cannot open without port.");
      }
  
      if (socket == null) {
        initSocket();
      }
  
      try {
        socket.connect(new InetSocketAddress(host, port), timeout);
        inputStream_ = new BufferedInputStream(socket.getInputStream(), 1024);
        outputStream_ = new BufferedOutputStream(socket.getOutputStream(), 1024);
      } catch (IOException iox) {
        close();
        throw new TTransportException(TTransportException.NOT_OPEN, iox);
      }
    }
docs: Connects the socket, creating a new socket object if necessary.