public class Controller {

  private Task<ObservableList<String>> task;

  @FXML
  private ListView listView;

  @FXML
  private ProgressBar progressBar;

  @FXML
  private Label progressLabel;

  public void initialize() {
    task = new Task<ObservableList<String>>() {
      @Override
      protected ObservableList<String> call() throws Exception {

        String[] names = {"Tim Buchalka",
                "Bill Rogers",
                "Jack Jill",
                "Joan Andrews",
                "Mary Johnson",
                "Bob McDonald"};

        ObservableList<String> employees = FXCollections.observableArrayList();

        for(int i=0; i<6; i++) {
          employees.add(names[i]);
          updateMessage(names[i] + " added to the list");
          updateProgress(i + 1, 6);
          Thread.sleep(200);
          updateMessage("list complete");
        }
        return employees;

      }
    };

    progressBar.progressProperty().bind(task.progressProperty());
    progressLabel.textProperty().bind(task.messageProperty());
    listView.itemsProperty().bind(task.valueProperty());
  }

  @FXML
  public void buttonPressed() {
    new Thread(task).start();
  }
}