private static Language getLanguageOrExit(final String lang) {
   Language language = null;
   boolean foundLanguage = false;
   final List<String> supportedLanguages = new ArrayList<>();
   for (final Language tmpLang : Languages.get()) {
     supportedLanguages.add(tmpLang.getShortName());
     if (lang.equals(tmpLang.getShortName())) {
       language = tmpLang;
       foundLanguage = true;
       break;
     }
   }
   if (!foundLanguage) {
     System.out.println(
         "Unknown language '" + lang + "'. Supported languages are: " + supportedLanguages);
     exitWithUsageMessage();
   }
   return language;
 }
 public static void main(String[] args) throws IOException {
   RuleSimplifier prg = new RuleSimplifier();
   prg.run(Languages.getLanguageForShortName("de"));
 }