private String getActualLangCode(String langCode) {
        if (langCode == null || "".equals(langCode)) {
            return defaultLangCode;
        }
        if (commonTokenMap.containsKey(langCode)) {
            return langCode;
        }
        tryToLoad(langCode);
        LangModel model = commonTokenMap.get(langCode);
        if (model == null) {
            return defaultLangCode;
        }
        return langCode;

    }
@param lang
@return pair of actual language code used and a set of common
tokens for that language
tika-eval/tika-eval-core/src/main/java/org/apache/tika/eval/core/tokens/CommonTokenCountManager.java