Logout Implement in Oracle ADF

The below code is required for logout in ADF applications.

public String logOut()  throws IOException{
        HttpSession session = null;
          FacesContext fctx = FacesContext.getCurrentInstance();
          ExternalContext ectx = fctx.getExternalContext();
          session = (HttpSession)ectx.getSession(false);
          HttpServletResponse response = (HttpServletResponse)ectx.getResponse();                      String currentPage = "faces/login.jspx";
          String url = ectx.getRequestContextPath()+"/adfAuthentication?logout=true&end_url=" + currentPage;
         try {
             response.sendRedirect(url);
              session.invalidate();
         } catch (Exception ex) {
             ex.printStackTrace();
          }
          fctx.responseComplete(); 
          return null;
      }

Thanks...