JavaFX Sequence Declaration

[TheServant]

Hi all,
I have only just started teaching myself JavaFX, and I am struggling with a few concepts. Does anyone know how to declare a class as a sequence? I had "object holders" which were simply classes which extended ArrayLists. These had custom functions, which is why I need them in JavaFX. For example in Java:

public class MyObjectHolder extends ArrayList<MyObject> {
 
    public MyObjectHolder() {
    }
 
    public void addObject(String name, Integer value) {
        this.add(new MyObject(name, value));
    }...

Obviously ArrayLists have been replaced with sequences, but now what?

Thanks for any help you can offer.