JavaFX Slider set color

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.Slider;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class Main extends Application {
   protected Text text = new Text("Show Colors");
   protected Slider slRed = new Slider();
   protected Slider slGreen = new Slider();
   protected Slider slBlue = new Slider();
   protected Slider slOpacity = new Slider();

   @Override/*from w w  w . ja  v  a  2 s .  c om*/
   public void start(Stage primaryStage) {
      // Create a stack pane for text
      StackPane paneForText = new StackPane(text);
      paneForText.setPadding(new Insets(20, 10, 5, 10));

      // Set slider properties
      slRed.setMin(0.0);
      slRed.setMax(1.0);
      slGreen.setMin(0.0);
      slGreen.setMax(1.0);
      slBlue.setMin(0.0);
      slBlue.setMax(1.0);
      slOpacity.setMin(0.0);
      slOpacity.setMax(1.0);

      // Create listeners
      slRed.valueProperty().addListener(ov -> setColor());
      slGreen.valueProperty().addListener(ov -> setColor());
      slBlue.valueProperty().addListener(ov -> setColor());
      slOpacity.valueProperty().addListener(ov -> setColor());
      slOpacity.setValue(1);

      // Create a grid pane for labeled sliders
      GridPane paneForSliders = new GridPane();
      paneForSliders.setAlignment(Pos.CENTER);
      paneForSliders.setVgap(5);
      paneForSliders.setHgap(5);
      paneForSliders.add(new Label("Red"), 0, 0);
      paneForSliders.add(slRed, 1, 0);
      paneForSliders.add(new Label("Green"), 0, 1);
      paneForSliders.add(slGreen, 1, 1);
      paneForSliders.add(new Label("Blue"), 0, 2);
      paneForSliders.add(slBlue, 1, 2);
      paneForSliders.add(new Label("Opacity"), 0, 3);
      paneForSliders.add(slOpacity, 1, 3);

      // Place nodes in a border pane
      BorderPane pane = new BorderPane();
      pane.setTop(paneForText);
      pane.setCenter(paneForSliders);

      // Create a scene and place it in the stage
      Scene scene = new Scene(pane, 250, 150);
      primaryStage.setTitle("java2s.com");
      primaryStage.setScene(scene);
      primaryStage.show();
   }

   /** Set the text color */
   private void setColor() {
      text.setFill(new Color(slRed.getValue(), slGreen.getValue(), slBlue.getValue(), slOpacity.getValue()));
   }
}