private synchronized void checkAndNotifyAboutCurrentAndPreviousMembers(String memberName, boolean isJoinEvent, boolean triggeredByGMS) { SortedSet<String> currentAliveAndReadyMembers = gms.getGroupHandle().getCurrentAliveAndReadyCoreView().getMembers(); AliveAndReadyView aView = gms.getGroupHandle().getPreviousAliveAndReadyCoreView(); SortedSet<String> previousAliveAndReadyMembers = new TreeSet<String>();