code: public void registerAccessTokenListener(AccessTokenListener accessTokenListener) {
      for(Authentication auth : authentications.values()) {
        if (auth instanceof OAuth) {
          OAuth oauth = (OAuth) auth;
          oauth.registerAccessTokenListener(accessTokenListener);
          return;
        }
      }
    }
docs: Configures a listener which is notified when a new access token is received.
  @param accessTokenListener