@Starki  - Please find the below response on why onTerminationEvent is not triggered

1. Cancelling the streaming query did not result in the termination of the stream properly. sleep of 5 seconds will allow termination of the underlying tasks when the stream is abruptly killed or cancelled, which would eventually result in sending the signal to the onTerminationEvent. 

It would be helpful if you add query.awaitAnyTermination() instead of query.stop() along with sleep of 5 seconds when abruptly cancelling. 

Please refer below for additional details. 

Reference: https://jaceklaskowski.gitbooks.io/spark-structured-streaming/content/spark-sql-streaming-StreamingQ...