title: cannot convert from String to ObservableValue<String>
body: <p>I'm making a program to manage and show data about airports, their flights and so on.
  The fact is that I have a tableView (in javafx) with several tableColumns, and I want to show some information (destiny, origin, company, etc) on each column so I typed this: </p>
  
  <pre><code>@FXML
  private TableColumn&lt;Flight, String&gt; destinoCol;
  
  @FXML
  private TableColumn&lt;Flight, String&gt; numCol;
  
  @FXML
  private MenuButton aeropuerto;
  
  @FXML
  private MenuButton tipo;
  
  @FXML
  private Button filtrar;
  
  @FXML
  private TableColumn&lt;Flight, LocalTime&gt; horaCol;
  
  @FXML
  private Button este;
  
  @FXML
  private DatePicker fecha;
  
  @FXML
  private TableColumn&lt;Flight, String&gt; origenCol;
  
  @FXML
  private Label retrasoLabel;
  
  @FXML
  private ImageView companiaImg;
  
  @FXML
  private VBox detalles;
  
  @FXML
  private Button todos;
  
  @FXML
  private ImageView avionImg;
  
  @FXML
  private Label tipoLabel;
  
  private mainVuelos m;
  private List&lt;Airport&gt; aeropuertos;
  private Data data;
  @FXML
  void initialize() {
      data = Data.getInstance();
      aeropuertos = data.getAirportList();
      List&lt;MenuItem&gt; ItemAeropuertos = new LinkedList&lt;MenuItem&gt;();
      for (int i = 0; i &lt; aeropuertos.size(); i++) {
          MenuItem item = new MenuItem(aeropuertos.get(i).getName());
          item.setOnAction((event) -&gt; cambiarAer(event));
          ItemAeropuertos.add(item);
      }
      aeropuerto.getItems().setAll(ItemAeropuertos);
      destinoCol.setCellValueFactory(cellData -&gt; cellData.getValue().getDestiny());
  }
  </code></pre>
  
  <p>The method <code>getDestiny()</code>, as it says returns the destiny of a specific flight as a <code>String</code> so obviously I cannot use the last instruction, it says</p>
  
  <pre><code>cannot convert from String to ObservableValue&lt;String&gt;
  </code></pre>
  
  <p>but I don't really know how to solve it in order to be able to show the destinies on that column.</p>