Pierwsza aplikacja JavaFX

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
 
public class JavaFXTestProgram extends Application {
    public static void main( String[] args ) {
        launch( args );
    }
    
    @Override
    public void start( Stage primaryStage ) {
        primaryStage.setTitle( "First JavaFX Test" );
        Button button = new Button();
        button.setText( "I am your first JavaFX Button. \nClick me to see a greeting in terminal." );
        button.setOnAction( new EventHandler<ActionEvent>() { 
            @Override
            public void handle( ActionEvent event ) {
                System.out.println( "Hello!" );
            }
        });
        
        StackPane stackPane = new StackPane();
        stackPane.getChildren().add( button );
        primaryStage.setScene( new Scene( stackPane, 400, 250));
        primaryStage.show();
    }
}