public boolean containsKey(final Object k) {
    return this._current.containsKey(k)
        || (this._parent != null && this._parent.containsKey(k));
  }
Check key in current Props then search in parent
dss-appconn/appconns/dss-eventchecker-appconn/src/main/java/com/webank/wedatasphere/dss/appconn/eventchecker/utils/Props.java