NullPointerException ResourceBundle.getString

W klasie kontorlera do javafx mam 2 funkcje jak poniżej. Jak w peirwszej wywołam resourceBundle.getString("directory"); nic się nie dzieje. Natomiast jak w drugiej wywołam to zwraca wyjątek NullPointerException.

private void loadLang(String lang) {
        locale = new Locale(lang);
        resourceBundle = ResourceBundle.getBundle("sample.lang", locale);
        copy.setText(resourceBundle.getString("copy"));
        delete.setText(resourceBundle.getString("delete"));
        move.setText(resourceBundle.getString("move"));
        changeLng.setText(resourceBundle.getString("changeLng"));
        rightTableViewColumnName.setText(resourceBundle.getString("nameColumn"));
        leftTableViewColumnName.setText(resourceBundle.getString("nameColumn"));
        rightTableViewColumSize.setText(resourceBundle.getString("sizeColumn"));
        leftTableViewColumSize.setText(resourceBundle.getString("sizeColumn"));
        resourceBundle.getString("directory");
    }

private ObservableList<FilesForTableView> getDirectoryContent(File file) {
        String[] fileList = file.list();
        String path = file.getPath();
        ObservableList<FilesForTableView> list = FXCollections.observableArrayList();
        if (fileList != null) {
            ArrayList<String> names = new ArrayList<String>(Arrays.asList(fileList));
            for (String s : names) {
                if (!s.equals("System Volume Information")) {
                    File file2 = new File(path + s);
                    Long size = file2.length();
                    resourceBundle.getString("directory");
                    if(file2.isDirectory()) {
                        //s=resourceBundle.getString("directory");
                    }
                    list.add(new FilesForTableView(s, size));
                }
            }
        }
        return list;
    }

W drugiej funkcji zgubiłeś getBundle().