}
                return new Pair<>(groupList.stream().distinct().toArray(n1 -> new String[n1]),
                        roleList.stream().distinct().toArray(n2 -> new String[n2]));
            });
        } catch (final ExecutionException e) {
            logger.warn("Failed to process a group cache.", e);
            return new Pair<>(StringUtil.EMPTY_STRINGS, StringUtil.EMPTY_STRINGS);