public static byte[] getSeniorClusterMemberID() {
        return cacheFactoryStrategy.getSeniorClusterMemberID();
    }
Returns a byte[] that uniquely identifies this senior cluster member or {@code null}
when not in a cluster.

@return a byte[] that uniquely identifies this senior cluster member or null when not in a cluster.
xmppserver/src/main/java/org/jivesoftware/util/cache/CacheFactory.java