@DELETE
 public Response logout(
     @Context HttpServletRequest request, @Context HttpServletResponse response) {
   // if session does not exist try and catch
   sessionHelper.setRequest(request);
   sessionHelper.getSession().invalidate();
   return Response.status(204).build();
 }
  @POST
  @Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML})
  public Response login(
      @FormParam("username") String username,
      @FormParam("password") String password,
      @Context HttpServletRequest request,
      @Context HttpServletResponse response) {
    String SessionVariableKeyOfUserId = USER_ID;
    sessionHelper.setRequest(request);
    if (miscHelper.authenticate(username, password)) {
      getSessionHelper().addVariableToSession(username, SessionVariableKeyOfUserId);
      return Response.status(201).build();
    }

    Error e = errorHelper.getInvalidCredentialError();
    return Response.status(Integer.valueOf(e.getCode())).entity(e).build();
  }