Buttons stop working after populating table view from database, in Javafx

Question

I am populating a Table View from a database, in Javafx. But as soon as the rows show up, the buttons in the same tab with the Table View stop working and throw null pointer exceptions. If I leave the Table View empty, the buttons work fine. The errors occur on the lines with tableColumn..., if I comment the first one out, the second one breaks and so on. Here's the code:

 @Override
  public void initialize(URL location, ResourceBundle resources) {
   Collection<Reservierung> list;
   Collection<Box> list1;
   try {
    list = service.listReservierung();
    tableColumnReservNr.setCellValueFactory(new PropertyValueFactory<Reservierung, Integer>("reservNr"));
    tableColumnReservName.setCellValueFactory(new PropertyValueFactory<Reservierung, String>("kundenName"));
    tableColumnReservVon.setCellValueFactory(new PropertyValueFactory<Reservierung, Timestamp>("von"));
    tableColumnReservBis.setCellValueFactory(new PropertyValueFactory<Reservierung, Timestamp>("bis"));
    AlleReservTable.getItems().setAll(list);
} catch (ServiceException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }

}

Answer 1

Turns out I was switching the scene the wrong way and that caused the buttons to stop working. Changed it thisway and now it works.