Why are the instantiated controls not displayed in the UI?

I have this login application. It is not starting the components correctly. I would like to know how to start them.

The code is the same as in the JavaFX workbook of the code house, in the login example.

package loginapp;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;
import javax.swing.JOptionPane;

/**
 *
 * @author sergi
 */
public class LoginApp extends Application {

    private AnchorPane pane;
    private TextField txtLogin;
    private PasswordField txtSenha;
    private Button btEntrar;
    private Button btSair;
    private static Stage stage;

    public static Stage getStage() {
        return stage;
    }

    private void initComponents() {
        pane = new AnchorPane();

        txtLogin = new TextField();

        txtSenha = new PasswordField();

        btEntrar = new Button("Entrar");

        btSair = new Button("Sair");

    }

    private void initLayout() {
        pane.setPrefSize(600, 200);
        pane.setStyle("-fx-background-color: blue;");

        txtLogin.setPromptText("Digite aqui o seu Login: ");
        txtLogin.setLayoutX((pane.getPrefWidth() - txtLogin.getLayoutX()) / 2);
        txtLogin.setLayoutY(50);

        txtSenha.setPromptText("Dgite aqui a sua senha");
        txtSenha.setLayoutX((pane.getPrefWidth() - txtSenha.getLayoutX()) / 2);
        txtSenha.setLayoutY(100);

        btEntrar.setLayoutX((pane.getPrefWidth() - btEntrar.getLayoutX()) / 2);
        btEntrar.setLayoutY(150);

        btSair.setLayoutX((pane.getPrefWidth() - btSair.getLayoutX()) / 2);
        btSair.setLayoutY(200);

    }

    private void initListeners() {
        btSair.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent event) {

                fecharAplicacao();
            }
        });

        btEntrar.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {

                if (txtLogin.getText().equals("admin") && txtSenha.getText().equals("casadocodigo")) {
                    //TODO Abrir tela vitrine
                } else {
                    JOptionPane.showMessageDialog(null, "Login e//ou senha invalidos", "Erro", JOptionPane.ERROR_MESSAGE); 
                }
            }
        });
    }

    private void fecharAplicacao() {

        System.exit(0);
    }

    @Override
    public void start(Stage stage) throws Exception {
        initComponents();
        initListeners();
        Scene scene = new Scene(pane);
        stage.setScene(scene);
        //Remove a opçao de maximizar a tela
        stage.setResizable(false);

        //Dá um titulo para a tela
        stage.setTitle("Login - GolFX");
        stage.show();
        initLayout();
        LoginApp.stage = stage;
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }    
}

The code does not contain compile errors, but does not execute the components ( txtLogin , txtSenha among others). However the style is loaded.