Run the app, and watch the movie. Just move the first column after the second one.

    @Override
    public void start(final Stage stage) throws Exception {
        stage.setTitle("TableView Demo");

        StackPane pane = new StackPane();

        TableView<Object> tableView = new TableView<Object>();
        TableColumn<Object, String> columnA = new TableColumn<Object, String>("A");
        TableColumn<Object, String> columnB = new TableColumn<Object, String>("B");
        tableView.getColumns().addAll(columnA, columnB);
        pane.getChildren().addAll(tableView);

        Scene scene = new Scene(pane, 300, 500, Color.DODGERBLUE);
        stage.setScene(scene);
        stage.show();
    }