Is there a way to display Integer values in JavaFx ComboBox with two digits?

I'm implementing a kind of clock in JavaFx. I have 2 combo boxes with integer values to select a time, one representing hours and the other minutes.

Is there a simple way of displaying the selected Integer with 2 digits in the ComboBox, for example instead of 1 there is 01?

One solution might be to have the combo box with string values and convert them to integers when I use them. However, I was wondering if there was another way to change the presentation of integers in the combo box properties directly.

Try using setCellFactory. As stated by @James_D in the commments and his edit to this answer, you also need to use setButtonCell.

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ListCell;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;


/**
 * JavaFX App
 */
public class App extends Application {

    @Override
    public void start(Stage stage) {

        ComboBox<Integer> cmb = new ComboBox();
        cmb.getItems().addAll(1, 2, 3, 10);

        cmb.setCellFactory(_ -> createCell());
        cmb.setButtonCell(createCell());
        
        cmb.setValue(1);
        
        Scene scene = new Scene(new StackPane(cmb));            
        stage.setScene(scene);
        stage.setMaximized(true);
        stage.show();
    }

    private ListCell<Integer> createCell() {
        return new ListCell<Integer>() 
        {            
            @Override protected void updateItem(Integer item, boolean empty) {
                super.updateItem(item, empty);
                
                if (item == null || empty) 
                {
                    setText(null);
                } 
                else 
                {
                    setText(String.format("%02d", item));
                }
            }
        };
    }

    public static void main(String[] args) {
        launch();
    }

}