HeaderController.java
final Tab tab = new Tab(department.getDepartmentName());
       tab.setOnSelectionChanged(new EventHandler<Event>() {
          @Override
            public void handle(Event event) {
                 if (tab.isSelected()) {
                     getInstance().setCenter(getFxml("/resources/center.fxml"));
                 }
             }
        });


CenterController.java
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
      departmentName = new TableColumn("Department");
      ordersTableColumnPersonName.setCellValueFactory(new PropertyValueFactory("department_name"));
      tableView().getColumns().add(departmentName);
      tableView().setItems(FXCollections.observableList(myList));
}

public void dispose() {
     table.getColumns().clear();
     table.getItems.clear();
     table = null;
}