TabPane is not working on my Application

I have a project from uni where I have to make an application with Java (in a model view controller format), and I want to make tabs in my application, but it doesn't seem to be working.

I looked up a lot of tutorials, and they all tell me the same way of how to use TabPane, but it doesn't work for me.

Here is the code I have in my Application Loader class:

    package main;

import controller.ModuleChooserController;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.stage.Stage;
import model.StudentProfile;
import view.ModuleChooserRootPane;

public class ApplicationLoader extends Application {

    private ModuleChooserRootPane view;

    @Override
    public void init() {
        //create model and view and pass their references to the controller
        StudentProfile model = new StudentProfile();
        view = new ModuleChooserRootPane();
        new ModuleChooserController(view, model);   
    }

    @Override
    public void start(Stage stage) throws Exception {
        //whilst you can set a min width and height (example shown below) for the stage window,
        //you should not set a max width or height and the application should
        //be able to be maximised to fill the screen and ideally behave sensibly when resized
        stage.setMinWidth(530); 
        stage.setMinHeight(500);

        TabPane tabPane = new TabPane();
        Tab tab = new Tab("Testing");
        tabPane.getTabs().add(tab);

        stage.setTitle("Final Year Module Chooser Tool");
        stage.setScene(new Scene(view));
        stage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }

}

I have the TabPane implemented, but nothing comes up. I also tried implementing the TabPane in my "view" package, but I had no luck there either.

Here is the code for the ModuleRootChooserPane:

    package view;

import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.VBox;

//You may change this class to extend another type if you wish
public class ModuleChooserRootPane extends BorderPane {

    private ButtonPane bp;
    private ProfileCreator profileCreator;


    public ModuleChooserRootPane() {

        //This sets the colour of background
        this.setStyle("-fx-background-color: #EDF1F3;");

        //Creates a new instance of the buttonPane (Used from ButtonPane.java) and ProfileCreator
        bp = new ButtonPane();
        profileCreator = new ProfileCreator();

        //This adds the padding on the left so that "submit" button is in line with text fields
        bp.setPadding(new Insets(0, 0, 0, 120));

        //Creates a new VBox which adds the ProfileCreator and the button pane
        VBox rootContainer = new VBox(profileCreator, bp);
        rootContainer.setPadding(new Insets(100,100,100,100));


        this.getChildren().add(rootContainer);
    }

}