scalafx borderpane layout error

Main.java

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TextAreaBuilder;
import javafx.scene.control.TreeView;
import javafx.scene.layout.BorderPaneBuilder;
import javafx.stage.Stage;
import javafx.scene.layout.BorderPane;

public class Main extends Application {
    @Override
    public void start(Stage stage) throws Exception {
        BorderPane root = BorderPaneBuilder.create().left(new TreeView<>()).center(
                new Label("hello")
        ).bottom(
                TextAreaBuilder.create().text("hello").build()
        ).build();
        Scene scene = new Scene(root, 800, 600);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        launch(Main.class, args);
    }
}

Main.scala

import scalafx.application.JFXApp
import scalafx.application.JFXApp.PrimaryStage
import scalafx.scene.Scene
import scalafx.scene.layout.BorderPane
import scalafx.scene.control.{Label, TreeView, TextArea}

object Main extends JFXApp {
  stage = new PrimaryStage {
    width = 800
    height = 600
    scene = new Scene {
      content = new BorderPane {
        left = new TreeView
        center = new Label("hello")
        bottom = new TextArea {
          text = "hello"
        }
      }
    }
  }
}