ShopController

private void deleteProduct(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<String> errors = new ArrayList<String>();
        if(request.getParameterMap().containsKey("id")){
            try {
                productService.delete(Integer.parseInt(request.getParameter("id")));
            } catch (NumberFormatException | DomainException e) {
                errors.add(e.getMessage());
            }
            request.setAttribute("errors", errors);
            gotoProductOverviewPage(request, response);
        } else {
            errors.add("Something went super wrong, system is broken :)");
            request.setAttribute("errors", errors);
            gotoDeleteProductPage(request, response);
        }
    }