Java tutorial
import java.util.ArrayList; import java.util.List; import javafx.collections.FXCollections; import javafx.collections.ListChangeListener; import javafx.collections.ObservableList; public class Main { public static void main(String[] args) { List<String> list = new ArrayList<String>(); ObservableList<String> observableList = FXCollections.observableList(list); observableList.addListener(new ListChangeListener() { @Override public void onChanged(ListChangeListener.Change change) { System.out.println("change!"); } }); observableList.add("item one"); list.add("item two"); System.out.println("Size: " + observableList.size()); } }