import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.layout.FlowPane;
import javafx.scene.control.Label;
import javafx.scene.control.ComboBox;
import javafx.collections.ObservableList;
import javafx.collections.FXCollections;
import javafx.geometry.Orientation;
  
public class Main extends Application {
    public static void main(String[] args) {
        Application.launch(args);
    }

    @Override
    public void start(Stage stage) throws Exception {          
        ObservableList<String> langs = FXCollections.observableArrayList("Java", "JavaScript", "C#", "Python");
        ComboBox<String> langsComboBox = new ComboBox<String>(langs);
        langsComboBox.getItems().add("Delphi"); // add new item
        langsComboBox.setValue("Delphi");

        Label lbl = new Label();         
        langsComboBox.setOnAction(event -> lbl.setText(langsComboBox.getValue()));

        FlowPane root = new FlowPane(10, 10, langsComboBox, lbl);
        Scene scene = new Scene(root, 300, 250);
        stage.setScene(scene);
        stage.setTitle("ComboBox in JavaFX");
        stage.show();
    }
}