JavaFX Scene create a simple calculator

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class Main extends Application {
   private TextField tfNumber1 = new TextField();
   private TextField tfNumber2 = new TextField();
   private TextField tfResult = new TextField();
   private Button btAdd = new Button("Add");
   private Button btSubtract = new Button("Subtract");
   private Button btMultiply = new Button("Mulitply");
   private Button btDivide = new Button("Divide");

   @Override/* www  .  java2s.co m*/
   public void start(Stage primaryStage) {
      // Create UI
      HBox hBox1 = new HBox(5);
      HBox hBox2 = new HBox(5);
      VBox vBox = new VBox(15);
      hBox1.getChildren().addAll(new Label("Number1: "), tfNumber1, new Label("Number2: "), tfNumber2,
            new Label("Result: "), tfResult);
      hBox2.getChildren().addAll(btAdd, btSubtract, btMultiply, btDivide);
      vBox.getChildren().addAll(hBox1, hBox2);

      // Set UI properties
      hBox1.setAlignment(Pos.CENTER);
      hBox2.setAlignment(Pos.CENTER);
      tfNumber1.setPrefColumnCount(4);
      tfNumber2.setPrefColumnCount(4);
      tfResult.setPrefColumnCount(4);
      tfResult.setEditable(false);
      vBox.setPadding(new Insets(2, 5, 0, 0));

      // Process events
      btAdd.setOnAction(e -> add());
      btSubtract.setOnAction(e -> subtract());
      btMultiply.setOnAction(e -> multiply());
      btDivide.setOnAction(e -> divide());

      // Create a scene and place it in the stage
      Scene scene = new Scene(vBox);
      primaryStage.setTitle("java2s.com");
      primaryStage.setScene(scene);
      primaryStage.show();
   }

   // Add number1 to number2
   private void add() {
      tfResult
            .setText(String.valueOf(Double.parseDouble(tfNumber1.getText()) + Double.parseDouble(tfNumber2.getText())));
   }

   // Subtract number1 from number2
   private void subtract() {
      tfResult
            .setText(String.valueOf(Double.parseDouble(tfNumber1.getText()) - Double.parseDouble(tfNumber2.getText())));
   }

   // Multiply number1 and number2
   private void multiply() {
      tfResult
            .setText(String.valueOf(Double.parseDouble(tfNumber1.getText()) * Double.parseDouble(tfNumber2.getText())));
   }

   // Divide number 1 from number2
   private void divide() {
      tfResult
            .setText(String.valueOf(Double.parseDouble(tfNumber1.getText()) / Double.parseDouble(tfNumber2.getText())));
   }
}