logout in oracle ADF / expiring session in ADF

One of the way of logging out user is ::

public String logout() throws IOException {
    ExternalContext ectx=FacesContext.getCurrentInstance().getExternalContext();
HttpServletResponse resp = (HttpServletResponse)ectx.getResponse();
HttpSession sess = (HttpSession)ectx.getSession(false);
sess.invalidate();
  resp.sendRedirect("login.jspx");
return null;
}