@Override
  public CqListener getCqListener() {
    ArrayList<CqListener> listeners = cqListeners;
    if (listeners == null) {
      return null;
    }
    synchronized (clSync) {
      if (listeners.size() == 0) {
        return null;
      }
      if (listeners.size() == 1) {
        return listeners.get(0);
      }
    }
    throw new IllegalStateException(
        "More than one Cqlistener exists.");
  }
Returns the CqListener set with the CQ
geode-core/src/main/java/org/apache/geode/cache/query/internal/cq/CqAttributesImpl.java