});
                        writer.flush();
                    }
                });
            }
        }
        throwValidationError(messages -> messages.addErrorsCouldNotFindBackupIndex(GLOBAL), this::asListHtml);
        return redirect(getClass()); // no-op
    }

    private Path getDocJsonPath() {
        return ResourceUtil.getClassesPath("fess_indices", "fess", "doc.json");
    }