Draw Square in javaFx

package javafxtest;

import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.Group;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;

public class Grphicsss extends Application {

    @Override public void start(Stage stage) {
       
        Group root = new Group();
        Scene scene = new Scene(root, 300, 300);
        scene.setFill(Color.LIGHTGRAY);
        Rectangle rectangle= new Rectangle(100, 100, 100,100);
        rectangle.setFill(Color.RED);
        root.getChildren().add(rectangle);
        stage.setScene(scene);
        stage.setTitle("Rectangle");
        stage.show();
    }

    public static void main(String[] args) {
        Application.launch(args);
    }
}
OUtPUT :