@Override
            public String getMailReturnPath() {
                return "******@****.***";
            }

            @Override
            public Integer getCrawlerSystemMonitorIntervalAsInteger() {
                return 60000;
            }
        };
        ComponentUtil.register(fessConfig, "fessConfig");

        File propFile = File.createTempFile("test", ".properties");

     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     * @throws NumberFormatException When the property is not integer.
     */
    Integer getCrawlerSystemMonitorIntervalAsInteger();

    /**
     * Get the value for the key 'crawler.hotthread.ignore_idle_threads'. <br>
     * The value is, e.g. true <br>