private void singleConfigsSync() {
        Optional<ConfigTable> configTable = readConfig(singleConfigChangeWatcherRegister.keys());

        // Config table would be null if no change detected from the implementation.
        configTable.ifPresent(config -> {
            config.getItems().forEach(item -> {
                String itemName = item.getName();
                WatcherHolder holder = singleConfigChangeWatcherRegister.get(itemName);
                if (holder == null) {
                    log.warn(
                        "Config {} from configuration center, doesn't match any WatchType.SINGLE watcher, ignore.",
                        itemName
                    );
                    return;
                }
                ConfigChangeWatcher watcher = holder.getWatcher();
                notifySingleValue(watcher, item);
            });
            if (log.isTraceEnabled()) {
                log.trace(
                    "Current configurations after the sync." + LINE_SEPARATOR + singleConfigChangeWatcherRegister.toString());
            }
        });
    }
Implement Config Watcher register using a periodic sync task.
oap-server/server-configuration/configuration-api/src/main/java/org/apache/skywalking/oap/server/configuration/api/FetchingConfigWatcherRegister.java