Как я могу получить вектор из потока класса java в другой класс?

Question

Я делаю многопоточный чат с сокетами в java. Я использовал векторы, так как они синхронизированы. Дело в том, что я хочу, чтобы данные, сохраненные вектором nameUser, находившимися в классе ManagementCommunication, в векторе user, расположенном в классе clientGUI. Я сделал getter / setter в классе clientGUI, чтобы ManagementCommunication мог отправить вектор через сеттер. Но когда я делаю ссылку, я получаю значение «внутри» метода установки только в clientGUI. Также, когда я использую геттер, он продолжает посылать 0.

Кроме того, ManagementCommunication и ServerCommunication находятся в одном пакете, но clientGUI нет.

cloneWhatsApp / Classes / ManagementCommunication Class [Он отвечает за инкапсуляцию всех сообщений клиента.]

    public class ManagementCommunication implements Runnable {


    private Socket socket;
    private ArrayList<Socket> UserList;
    private Vector<String> nameUser;
    private Map<String, Socket> map;
    private DataOutputStream sendInfo;
    private DataInputStream getInfo;
    private Gson gson = new Gson();
    private SubjectHelper subjectHelper = new SubjectHelper();
    private boolean flag = true;
    private String receiver; 

   //Empty Constructor
    public ManagementCommunication() {

    }


    /**
     *
     * @param socket
     * @throws IOException
     */

//Its constructor receives from serverCommunication the socket, vector and map.
 public ManagementCommunication(Socket socket, Vector<String> nomeUsuario, Map<String, Socket> map) throws IOException {
        this.socket = socket;
        this.nameUser=nomeUsuario;
        this.map=map;

        //Opening the data streams.
        getInfo = new DataInputStream(this.socket.getInputStream());
        sendInfo = new DataOutputStream(this.socket.getOutputStream());
    }


    /**
     *
     * @throws IOException
     */
    public void getInfo() throws IOException {
        while (socket.isConnected()) {
            //receiving data
            String message = getInfo.readUTF();
            Message m = gson.fromJson(message, Message.class);
            //we get the receiver
            receiver = m.sendTo;   

            String user = m.getUser();
            //
            if(!nameUser.contains(user)){

                 //Add to vector
                nameUser.addElement(m.getUser());
                map.put(m.getUsuario(), socket);
                clientGUI.setUser(nameUser);   //SETTER TO SEND THE VALUE TO CLIENTGUI         
             }           
                //send message to all connected clients 
                ServerCommunication.getInstance().sendMessageUsersConnected(m);

        }
    }

    /**
     *  
     *
     * @param enviadoPor
     * @param mensajes 
     * @throws IOException
     */
    public void sendInfo(String sendBy,String sendTo, String messages) throws IOException {
         Message m = new Message(sendBy, sendTo, messages, new Date());
        sendInfo.writeUTF(gson.toJson(m));
        sendInfo.flush();
    }

    @Override
    public void run() {
        try {
            getInfo();
        } catch (EOFException ex) { 
            subjectHelper.notify(ManagementCommunication.class, "Disconnecting", TipoNotificacion.DESCONEXION);
        } catch (IOException ex) {
            Logger.getLogger(ManagementCommunication.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

cloneWhatsApp / Classes / ServerCommunication class

public class ServerCommunication implements Runnable {

    private static ServerCommunication instance;
    private ServerSocket server;
    private List<ManagementCommunication> ManagementCommunicationList = new ArrayList<>();
    private boolean running;
    private SubjectHelper subjectHelper = new SubjectHelper();
    public static Map<String, Socket> map = null;
    public static Vector<String> nameUser = null;    // thread security

    private ServerCommunication() {
    }

    /**
     * @return
     */
    public static ServerCommunication getInstance() {
        if (instance == null) {
            instance = new ServerCommunication();
        }
        return instance;
    }

    /**
     * @param port
     * @throws Exception
     */
    public void startServer(int port) throws Exception {
        //initializing
        nameUser = new Vector<String>();     
        map = new HashMap<String, Socket>();
        // 
        server = new ServerSocket(port); 
        running = true;
        new Thread(this).start();
    }

    /**
     *
     */
    public void stopServer() { 
        running = false;
        try {
            server.close();
            server = null;
            ManagementCommunicationList.clear();
            subjectHelper.removeAllObserver();
        } catch (IOException ex) {
            Logger.getLogger(ServerCommunication.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public void sendMessageUsersConnected(Message message) {
        if(message.getMessage().equals("")){
            return;
        }
        for (ManagementCommunication m : ManagementCommunicationList) {
            try {
                m.sendInfo(message.getUser(), message.getsendTo(), message.getMessage());
            } catch (IOException ex) {
                Logger.getLogger(ServerCommunication.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

    }


    @Override
    public void run() {
        while(running){
            try {

                //Opening socket.
                Socket s = server.accept(); 
                //
                subjectHelper.notify(ServerSocket.class, "nueva conexion", TipoNotificacion.CONEXION);

                //send to constructor 
                ManagementCommunication m = new ManagementCommunication(s,nameUser, map);
                //
                m.addObservadorListener((Class clase, Object argumento, Enum anEnum) -> {
                    subjectHelper.notify(clase, argumento, anEnum);
                });
                //Add object to list
                ManagementCommunicationList.add(m);   

                //starting thread
                new Thread(m).start();
            } catch (IOException ex) {
                Logger.getLogger(ServerCommunication.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

cloneWhatsApp / Клиент GUI Класс

    public class clientGUI extends javax.swing.JDialog {


    private Vector<String> user = new Vector<>();
    private DataOutputStream dout;
    private DataInputStream din;
    private Gson gson;
    private clientSignInGUI referenceClientSignInGUI; 
    private SubjectHelper subjectHelper = new SubjectHelper();
    boolean flag = true;
    public static String receiver = "";
    List<String> usuarios = new ArrayList<>();
    DefaultListModel listModel;



    public clientGUI(java.awt.Frame parent, boolean modal) {
        super(parent, modal);
        initComponents();
        init();
    }    

    private clientGUI() {  
    }

     public void init(){

         //Add model
         listModel = new DefaultListModel();
         list.setModel(listModel);
         list.setCellRenderer(new listUser());  //listUser is a class with a ListRenderer.

         }

         //HERE ITS WHERE I WANT TO PRINT THE VALUES
         ActionListener a1 = new ActionListener(){
             @Override
             public void actionPerformed(ActionEvent e) {
                 if(e.getSource()== btnChat){
                      for(int i = 0; i<getUser().size();i++){
                    //IT PRINTS 0
                    System.out.println(getUser().get(i));
        }
                 }
             }

        };

         btnChat.addActionListener(a1);

        //
        name.setText(""+referenceClientSignInGUI.username);

        //starts client connection
        gson = new Gson();
        try {
            conect();
        } catch (IOException ex) {
            Logger.getLogger(clientGUI.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    private void conect() throws IOException
    {

        din = new DataInputStream(referenceClientSignInGUI.socket.getInputStream());
        dout = new DataOutputStream(referenceClientSignInGUI.socket.getOutputStream());


                new Thread(() -> {
            try {
                sendMessage();
                getInfo();
            } catch (IOException ex) {
                Logger.getLogger(clientGUI.class.getName()).log(Level.SEVERE, null, ex);
            }
        }).start();
    }

    //Get vector 
    public static Vector<String> getUser() {
        System.out.println("value: "+user.size()); // Prints 0
        return user;
    }

    //Set vector
    public static void setUser(Vector<String> us) {
        clientGUI.user = us;
        //HERE IT PRINTS THE CORRECT VALUE BECAUSE I USE "us", using "user" it prints 0.
        System.out.println("UserList size: "+us.size()); 
    }

    private void getInfo() throws IOException {
        while (true) {
            String info = din.readUTF(); //Reads what the server is sending
            Message m = gson.fromJson(info, Message.class);  
           showMessagesReceived(m); //prints to client

        }
    }

 //Method reference to class clientSignInGUI
    public void getInfo(clientSignInGUI tae) {
        this.referenceClientSignInGUI = tae;
    } 

//Send messages to clients
   private void showMessagesReceived(Mensaje m) {
        displayMessage.append(String.format("[%s]: %s", m.getUser(), m.getMessage())+"\n");
    }

private void sendMessage() throws IOException {

           if(flag){
            flag = false;  
            Message m =new Message(referenceClientSignInGUI.username, receiver, txtMessage.getText(), new Date());
            dout.writeUTF(gson.toJson(m));
            dout.flush();
                }else{ 
                Message m =new Message(referenceClientSignInGUI.username, receptor, txtMessage.getText(), new Date());
                dout.writeUTF(gson.toJson(m));
                dout.flush();
                txtMessage.setText("");
                }
    }

     public static String getReceiver() {
        return receiver;
    }
      public static void setReceiver(String receiver) {
        clientGUI.receiver = receiver;
    }
}

Обычно при нажатии btnChat отображается обновленный вектор user, но отправляется ноль. Если есть другой способ получить значение, пожалуйста, дайте мне знать, спасибо заранее.