String value = null;
        assertNull(systemHelper.normalizeLang(value));

        value = "";
        assertNull(systemHelper.normalizeLang(value));

        value = "_ja";
        assertNull(systemHelper.normalizeLang(value));

        value = "ja";
        assertEquals("ja", systemHelper.normalizeLang(value));

        value = " ja ";

                        langSet.clear();
                        break;
                    }
                    final String normalizeLang = systemHelper.normalizeLang(lang);
                    if (normalizeLang != null) {
                        langSet.add(normalizeLang);
                    }
                }
            }
            if (!langSet.isEmpty()) {

                        langSet.add(Constants.ALL_LANGUAGES);
                    } else {
                        final String normalizeLang = systemHelper.normalizeLang(lang);
                        if (normalizeLang != null) {
                            langSet.add(normalizeLang);
                        }
                    }
                }
            }

            return defaultLang;
        }

        return normalizeLang(value);
    }

    /**
     * Normalizes a language string.
     *
     * @param value The language string to normalize.
     * @return The normalized language string.
     */
    public String normalizeLang(final String value) {
        if (StringUtil.isBlank(value)) {
            return null;
        }

        @Override
        public long getCurrentTimeAsLong() {
            return System.currentTimeMillis();
        }

        @Override
        public String normalizeLang(String lang) {
            if ("en".equals(lang) || "ja".equals(lang)) {
                return lang;
            }
            return null;
        }

    }