code: public String getRestUrl(String urlKey, Boolean addClientId) throws UnsupportedEncodingException {
          return getRestUrl(urlKey, addClientId, null, null);
      }
docs: Gets REST url.
  
  @param urlKey      Url key.
  @param addClientId Denotes whether client identifier should be composed into final url.
  @return Final REST url.
  @throws UnsupportedEncodingException