code: public static String get(String key)
      {
          key = key.toLowerCase();
          for ( String f : fieldsArr ) {
              if ( key.equals(f) ) {
                  return f;
              }
          }
          
          return key;
      }
docs: get the entity string by the specified key
  Note well, this may puzzle you more or less
  thousands of word items quote the same string constants
  of course, this will save lots of runtime memory (constants string pool)