public void execute(final WebClient webClient) throws SubscriptionException {
  HtmlPage loginPage = null;;
  try {
    // Get the page, fill in the credentials and submit the login form
    loginPage = webClient.getPage(url);
    this.loginPage = loginPage;
    final HtmlForm loginForm = loginPage.getFormByName(nameOfLoginForm);
    final HtmlTextInput userfield = loginForm.getInputByName(nameOfUserField);
    userfield.setValueAttribute(username);
    final HtmlPasswordInput passwordfield = loginForm.getInputByName(nameOfPasswordField);
    passwordfield.setValueAttribute(password);
    final HtmlPage pageAfterLogin = (HtmlPage) loginForm.submit(null);
    output = pageAfterLogin;
 [...]