EDIT

        try {

            // render

            render(entity, writer, jsonpCallback, request, response);

        } catch (Exception e) {

            writer.write("Error when rendering a response object of type " + (entity == null? "null" :entity.getClass().getCanonicalName()) + System.lineSeparator() + System.lineSeparator());

            if (e.getCause() != null) {

                //leave out the wrapping JSONException

                e.getCause().printStackTrace(writer);

            }else {

                writer.write("No stacktrace");

            }

            throw e;

        }