code: private void fireRosterExchangeListeners(Jid from, Iterator<RemoteRosterEntry> remoteRosterEntries) {
          RosterExchangeListener[] listeners;
          synchronized (rosterExchangeListeners) {
              listeners = new RosterExchangeListener[rosterExchangeListeners.size()];
              rosterExchangeListeners.toArray(listeners);
          }
          for (RosterExchangeListener listener : listeners) {
              listener.entriesReceived(from, remoteRosterEntries);
          }
      }
docs: Fires roster exchange listeners.