code: protected OAuthProviderToken createOAuthToken(ConsumerAuthentication authentication) {
      return getTokenServices().createUnauthorizedRequestToken(authentication.getConsumerDetails().getConsumerKey(),
                                                               authentication.getOAuthParameters().get(OAuthConsumerParameter.oauth_callback.toString()));
    }
docs: Create the OAuth token for the specified consumer key.
  
  @param authentication The authentication request.
  @return The OAuth token.