How come the server isn't getting the message (java)

Question

public class Client extends Application {
    static TextField output = new TextField();

    @Override
    public void start(Stage stage) {
        GridPane root = new GridPane();
        root.addRow(0, output);

        Scene scene = new Scene(root, 640, 480);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        try (Socket socket = new Socket("127.0.0.1", 1234)) {
            // writing to server
            PrintStream out = new PrintStream(
                    socket.getOutputStream(), true);

            // reading from server
            BufferedReader in
                    = new BufferedReader(new InputStreamReader(
                    socket.getInputStream()));

            output.setOnAction(e ->{
                String message = output.getText();
                output.clear();
                out.println(message);
                out.flush();
            });

        } catch (IOException e) {
            e.printStackTrace();
        }
        launch();
    }
}

original client code that was working. it just took input from the console/terminal rather than a text field.

class Client2 {
    // driver code
    public static void main(String[] args)
    {
        // establish a connection by providing host and port
        // number
        try (Socket socket = new Socket("localhost", 1234)) {

            // writing to server
            PrintWriter out = new PrintWriter(
                    socket.getOutputStream(), true);

            // reading from server
            BufferedReader in
                    = new BufferedReader(new InputStreamReader(
                    socket.getInputStream()));

            // object of scanner class
            Scanner sc = new Scanner(System.in);
            String line = null;

            while (!"exit".equalsIgnoreCase(line)) {

                // reading from user
                line = sc.nextLine();

                // sending the user input to server
                out.println(line);
                out.flush();

                // displaying server reply
                System.out.println("GroupProject.Server replied "
                        + in.readLine());
            }

            // closing the scanner object
            sc.close();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }
}

there is more to the server class but it just handles connecting clients

class Server {
    // ClientHandler class
    private static class ClientHandler implements Runnable {
        private final Socket clientSocket;

        // Constructor
        public ClientHandler(Socket socket)
        {
            this.clientSocket = socket;
        }

        public void run()
        {
            PrintWriter out = null;
            BufferedReader in = null;
            try {

                // get the outputstream of client
                out = new PrintWriter(
                        clientSocket.getOutputStream(), true);

                // get the inputstream of client
                in = new BufferedReader(
                        new InputStreamReader(
                                clientSocket.getInputStream()));

                String line;
                while ((line = in.readLine()) != null) {

                    // writing the received message from
                    // client
                    System.out.printf(
                            " Sent from the client: %s\n",
                            line);
                    out.println(line);
                }
            }
            catch (IOException e) {
                e.printStackTrace();
            }
            finally {
                try {
                    if (out != null) {
                        out.close();
                    }
                    if (in != null) {
                        in.close();
                        clientSocket.close();
                    }
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

The goal is to change the chatroom's functionality from the console/terminal to a JavaFX scene. Thought it would be as simple as changing the way the client sends the user's input but it doesn't seem like that's the case.