* @return 変換された{@link Date}
     */
    protected static Date toDate(final String str, final DateFormat format) {
        final ParsePosition pos = new ParsePosition(0);
        final Date date = format.parse(str, pos);
        if (date == null) {
            return null;
        }
        final int index = pos.getIndex();
        if (index == 0) {
            return null;
        }

            System.setProperty("fess.version", version);
            System.setProperty("fess.product.version", productVersion);
        } catch (final Exception e) {
            throw new FessSystemException("Failed to parse project.properties.", e);
        }
    }

    @PreDestroy
    public void destroy() {
        shutdownHookList.forEach(action -> {
            try {
                action.run();

     * @return 変換された{@link Date}
     */
    protected static Date toDate(final String str, final DateFormat format) {
        final ParsePosition pos = new ParsePosition(0);
        final Date date = format.parse(str, pos);
        if (date == null) {
            return null;
        }
        final int index = pos.getIndex();
        if (index == 0) {
            return null;
        }

     * @return 変換された{@link Date}
     */
    protected static Date toDate(final String str, final DateFormat format) {
        final ParsePosition pos = new ParsePosition(0);
        final Date date = format.parse(str, pos);
        if (date == null) {
            return null;
        }
        final int index = pos.getIndex();
        if (index == 0) {
            return null;
        }