code: public String get(String key, String defaultString) {
      if (!containsKey(key)) {
        return defaultString;
      }
      return get(key);
    }
docs: Gets the value for <code>key</code> or <code>defaultString</code> if not found.
  
  @param key key to get value for
  @param defaultString default string if key not found
  @return value of <code>defaultString</code> if not found