}
                        });
                        final List<String> newGroupList = stream(user.getGroupNames()).get(stream -> stream.collect(Collectors.toList()));
                        stream(user.getGroupNames()).of(stream -> stream.forEach(name -> {
                            if (oldGroupList.contains(name)) {
                                oldGroupList.remove(name);

            return name;
        }

        @Override
        public String[] getRoleNames() {
            return new String[0];
        }

        @Override
        public String[] getGroupNames() {
            return new String[0];
        }

        @Override
        public String[] getPermissions() {
            return permissions;
        }

    }