Question

True or False. When clicking the button, the program displays OK1 OK2. When clicking the button, the program displays OK1. When clicking the button, the program displays OK2. The program has a compile error, because the setOnAction method is invoked twice.

Answer 1

Answer:

False, The program has no compile error.

Explanation:

import javafx.application.Application;

import javafx.scene.Scene;

import javafx.scene.control.Button;

import javafx.stage.Stage;

public class Test extends Application {

 @Override // Override the start method in the Application class

 public void start(Stage primaryStage) {

   // Create a button and place it in the scene

   Button btOK = new Button("OK");

   btOK.setOnAction(e -> System.out.println("OK 1"));

   btOK.setOnAction(e -> System.out.println("OK 2"));

   Scene scene = new Scene(btOK, 200, 250);

   primaryStage.setTitle("MyJavaFX"); // Set the stage title

   primaryStage.setScene(scene); // Place the scene in the stage

   primaryStage.show(); // Display the stage

 }

 public static void main(String[] args) {

   launch(args);

 }

}

Java has an inline compiler, so if the line of code for an event is repeated twice and they both are not segmented, they will be compiled consecutively.