ConnectionTable getConTable() {
    ConnectionTable result = conTable;
    if (result == null) {
      stopper.checkCancelInProgress(null);
      throw new DistributedSystemDisconnectedException("tcp layer has been shutdown");
    }
    return result;
  }
this is the server socket listener thread's run loop
geode-core/src/main/java/org/apache/geode/internal/tcp/TCPConduit.java