JavaFX Tutorial 14 Slider Event ChangeListener JavaFX

JavaFX Tutorial 14 Slider Event ChangeListener JavaFX
Code source :
@Override
public void start(Stage primaryStage) {
HBox h = new HBox();
Slider s = new Slider();
@Override
public void changed(ObservableValue?? extends Number? observable, Number oldValue, Number newValue) {
}
});

Scene sc = new Scene(h,600,400);
}
Libraries Importing :

[bamideletewogbade]

good morning my dear friend and teacher how was your night and family trust you are good? so yesterday while working on the slider I ran into some issues don't know how but magically I was able to debug and it ran but I would like you to please explain the addListener part to the lb.setText("Valom = " + (int)s.getValue()); part ... I understand pretty much what it does but things like the <Number> and Number oldValue, Number newValue are confusing .... starting on my piechart hahaha ... have a great day brother.