It works !

ChatApp/app/src/main/java/ChatAppClient.java

@@ -4,7 +4,7 @@ import java.net.InetSocketAddress;
 
 public class ChatAppClient {
     public static void main(String[] args) {
-        ClientConsole console = new ClientConsole(new InetSocketAddress("192.168.163.131", 6665));
+        ClientConsole console = new ClientConsole(new InetSocketAddress("localhost", 6665));
         try {
             console.joinThread();
         } catch (InterruptedException e) {

ChatApp/app/src/main/java/client/ClientGuiController.java

@@ -1,8 +1,15 @@
 package client;
 
+import javafx.application.Platform;
 import javafx.fxml.FXML;
+import javafx.scene.control.Alert;
+import javafx.scene.layout.Border;
+import javafx.scene.layout.BorderPane;
+import javafx.stage.Stage;
 import network.protocol.packets.ServerResponsePacket;
 
+import java.net.InetSocketAddress;
+import java.net.SocketException;
 import java.time.Instant;
 import java.util.List;
 
@@ -10,30 +17,44 @@ public class ClientGuiController implements ClientListener {
 
     private Client client;
 
+    @FXML
+    private BorderPane vueContainer;
+
     public void setClient(Client client) {
         this.client = client;
     }
 
-    @FXML
-    public void initialize() {
-
-    }
+@FXML
+public void initialize() throws SocketException {
+    client = new Client(new InetSocketAddress("localhost", 6665), this, UsernameSingleton.getInstance().getUsername());
+    Platform.runLater(() -> {
+        Stage stage = (Stage) vueContainer.getScene().getWindow();
+        stage.setOnCloseRequest(event -> {
+            client.close();
+        });
+    });
+}
 
     @Override
     public void handleDisconnect() {
-
+        System.out.println("Disconnected");
     }
 
     @Override
     public void handleConnexionError() {
-
+        System.out.println("Connection error");
+        System.out.println(UsernameSingleton.getInstance().getUsername());
     }
 
     @Override
     public void handleConnect() {
-
+        Platform.runLater(() -> {
+            Alert alert = new Alert(Alert.AlertType.INFORMATION);
+            alert.setTitle("Connection");
+            alert.setHeaderText("Connection to the server successful");
+            alert.showAndWait();
+        });
     }
-
     @Override
     public void handleChatMessage(Instant time, String chatter, String content) {
 

ChatApp/app/src/main/java/client/ClientLoading.java

@@ -15,71 +15,33 @@ import java.util.List;
 
 import static utilities.FxUtilities.centerStage;
 
-public class ClientLoading implements ClientListener {
+public class ClientLoading {
     @FXML
     private Arc spinnerArc;
 
-    private Client client;
-
     public void initialize() throws IOException, InterruptedException {
         // Création de l'animation de rotation
         RotateTransition rotate = new RotateTransition(Duration.seconds(1), spinnerArc);
         rotate.setByAngle(360);
         rotate.setCycleCount(RotateTransition.INDEFINITE);
         rotate.play();
-    }
 
-    public void setClient(Client client) {
-        this.client = client;
+//        new Thread(() -> {
+//            try {
+//                Thread.sleep(2000);
+//                login();
+//            } catch (IOException | InterruptedException e) {
+//                e.printStackTrace();
+//            }
+//        });
     }
 
     public void login() throws IOException {
         var loader = new FXMLLoader(getClass().getResource("/client/clientVue.fxml"));
         loader.load();
-        client.changeCallback(loader.getController());
-        ((ClientGuiController) loader.getController()).setClient(client);
         Stage stage = (Stage) spinnerArc.getScene().getWindow();
         stage.setScene(new Scene(loader.getRoot(), 800, 600));
         centerStage(stage);
         stage.getScene().getStylesheets().add(getClass().getResource("clientStyle.css").toExternalForm());
     }
-
-    @Override
-    public void handleDisconnect() {
-        System.out.println("Disconnected");
-    }
-
-    @Override
-    public void handleConnexionError() {
-        System.out.println("Connection error");
-    }
-
-    @Override
-    public void handleConnect() {
-        try {
-            login();
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
-    }
-
-    @Override
-    public void handleChatMessage(Instant time, String chatter, String content) {
-
-    }
-
-    @Override
-    public void handleRoomList(List<String> roomNames) {
-
-    }
-
-    @Override
-    public void handleServerResponse(ServerResponsePacket.Response response) {
-
-    }
-
-    @Override
-    public void handleActualRoom(String roomName) {
-
-    }
 }

ChatApp/app/src/main/java/client/ClientLogin.java

@@ -5,9 +5,7 @@ import javafx.fxml.FXMLLoader;
 import javafx.scene.Scene;
 import javafx.scene.control.TextField;
 import javafx.stage.Stage;
-import client.ClientGui;
 import java.io.IOException;
-import java.net.InetSocketAddress;
 
 import static utilities.FxUtilities.centerStage;
 
@@ -21,10 +19,9 @@ public class ClientLogin {
         if(username.isEmpty()) {
             return;
         }
+        UsernameSingleton.getInstance().setUsername(username);
         var loader = new FXMLLoader(getClass().getResource("/client/clientLoading.fxml"));
-        Client client = new Client(new InetSocketAddress("localhost", 6665), loader.getController(), username);
         loader.load();
-        ((ClientLoading) loader.getController()).setClient(client);
         Stage stage = (Stage) usernameField.getScene().getWindow();
         stage.setScene(new Scene(loader.getRoot(), 800, 600));
         centerStage(stage);

ChatApp/app/src/main/java/client/UsernameSingleton.java

@@ -0,0 +1,24 @@
+package client;
+
+public class UsernameSingleton {
+    private static UsernameSingleton instance;
+    private String username;
+
+    private UsernameSingleton() {
+    }
+
+    public static UsernameSingleton getInstance() {
+        if (instance == null) {
+            instance = new UsernameSingleton();
+        }
+        return instance;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+}