@Override
    public void joinedCluster(byte[] nodeID) {
        // Another node joined a cluster that we're already part of. It is expected that
        // the implementation of #joinedCluster() as executed on the cluster node that just
        // joined will synchronize all relevant data. This method need not do anything.
    }
Returns the number of milliseconds to elapse between clearing of idle server sessions.

@return the number of milliseconds to elapse between clearing of idle server sessions.
xmppserver/src/main/java/org/jivesoftware/openfire/SessionManager.java