MultiClient-Server, socket implementation in javaFX

I am creating a desktop app with javaFX. In this app I have to check for new requests from other clients to the current user; if both the current user (receiver) and another remote client (sender) are active, using sockets.

(doubt is specified at the end)

I will try to keep the things as simple as possible here.

There are four Classes related with the socket implementation as follows

> Server

> ClientHandler

> Client

> ServerConnection

1) Server

public class Server {
    private static final int PORT = 9090;
    private static HashMap<String,ClientHandler> clients = new HashMap<>();

    private static ExecutorService pool = Executors.newFixedThreadPool(4);
    public static void main(String[] args) throws IOException {
        ServerSocket listener = new ServerSocket(PORT);
        BufferedReader in;
        while (true) {
            System.out.println("server is waiting for client to connect");
            Socket client = listener.accept();
            in = new BufferedReader(new InputStreamReader(client.getInputStream()));
            String id = in.readLine();
            System.out.println(id);
            ClientHandler clientThread = new ClientHandler(client,clients,id);
            clients.put(id,clientThread);
            pool.execute(clientThread);
        }
    }
}

2) ClientHandler

public ClientHandler(Socket clientSocket, HashMap<String, ClientHandler> clients, String id) throws IOException {
        this.id = id;
        this.client = clientSocket;
        this.clients = clients;
        in = new BufferedReader(new InputStreamReader(client.getInputStream()));
        out = new PrintWriter(client.getOutputStream(), true);
    }

    @Override
    public void run() {
        try {
            while (true) {
                String request = in.readLine();
                System.out.println(request);
                if(request.startsWith("say")){
                    outToAll(request);
                }
            }
        } catch (Exception e) {
            System.out.println(e);
        } finally {
            try {
                in.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            out.close();
        }
    }
    //this method is used to send message to all the active clients
    public void outToAll(String msg){
            clients.forEach((key,client)->{
                  c.out.println(msg);
            });
        }

3)Client

public Client(String id) throws IOException {
        this.id = id;
        this.socket = new Socket(IP_ADDRESS, PORT);
        this.serverConnection = new ServerConnection(socket);
        this.keyboard = new BufferedReader(new InputStreamReader(System.in));
        this.out = new PrintWriter(socket.getOutputStream(), true);
    }

    @Override
    public void run() {
        new Thread(serverConnection).start();
        try {
            out.println(id);
            while (true) {
                String command = keyboard.readLine();
                if (command.equals("quit")) break;
                out.println(command);
            }
        } catch (Exception e) {
            System.out.println(e);
        }
        out.close();
        try {
            socket.close();
            keyboard.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void stopSocket() throws IOException {
        socket.close();
    }

4) ServerConnection

//Server connection is connection from client side to the server.which reads message from server and just prints into the console

public ServerConnection(Socket server) throws IOException {
        this.server = server;
        this.in = new BufferedReader(new InputStreamReader(this.server.getInputStream()));
    }
    @Override
    public void run() {
        try{
            while (true){
                String msg = in.readLine();
                if(msg == null) break;
                System.out.println("Server says > "+ msg);
            }
        }catch (Exception e){
            System.out.println(e);
        }finally {

        }
    }

So these are my socket service related classes.

>As I am using javaFX each Client Runnable class should run on its own thread, thus to achieve this I have create a thread in side my javaFX Controller Named HomeController which is called whenever a client is logged in. HomeController then creates a client Thread like shown below

I hope that this the correct way to do so, as i need another thread so that client will

not block the javafx ui thread

    //as I have access to the `id` and already have created a Client object
    // I hope that this the correct way to do so
    this.client = new Client(id);
    new Thread(client).start();

And whenever a client is logged out, I close the Client Socket as

    //above created client
    client.stopSocket();

Thus in this way i have created separate client thread for each client connected to the server.

Doubt

I start multiple javafx app instance with and login with different user ids.

>So according to the implementation, when I will type something in the client console it should be printed in each and every console of other clients too . But this doesn't happen all the time . some client do get message some don't and sometimes no one gets the message. I guess some clients are get blocked and I can't understand.

>So for testing purpose, I created another project with same 4 classes and rather than defining Client class as runnable i created a main method in it. And launched multiple instances of Client class. Keeping rest of the things same. This implementation works just great without any flaw.

Please help me through this it's been 4 days I am facing this issue.