public static long getClusterTime() {
        // use try/catch here for backward compatibility with older plugin(s)
        try { return cacheFactoryStrategy.getClusterTime(); }
        catch (AbstractMethodError ame) {
            log.warn("Cluster time not available; check for update to hazelcast/clustering plugin");
            return localCacheFactoryStrategy.getClusterTime();
        }
    }
Gets the pseudo-synchronized time from the cluster. While the cluster members may
have varying system times, this method is expected to return a timestamp that is
synchronized (or nearly so; best effort) across the cluster.

@return Synchronized time for all cluster members
xmppserver/src/main/java/org/jivesoftware/util/cache/CacheFactory.java