private synchronized static void handleDisconnect(Connection con) {
        if (periodicPingExecutorService != null) {
            instances.remove(con);

            if (instances.isEmpty()) {
                periodicPingExecutorService.shutdownNow();
                periodicPingExecutorService = null;
            }
        }
    }
private synchronized static void handleDisconnect(Connection con) {
        if (periodicPingExecutorService != null) {
            instances.remove(con);

            if (instances.isEmpty()) {
                periodicPingExecutorService.shutdownNow();
                periodicPingExecutorService = null;
            }
        }
    }
private synchronized static void handleDisconnect ( Connection con ) { if ( periodicPingExecutorService != null ) { instances . remove ( con ) ; if ( instances . isEmpty ( ) ) { periodicPingExecutorService . shutdownNow ( ) ; periodicPingExecutorService = null ; } } }
/*
Stop the executor service if all monitored connections are disconnected.
/ * Stop the executor service if all monitored connections are disconnected .