Please throw a warning message to the user when automatically modifying parameters or algorithms. Doing this silently makes it extremely difficulty to debug and fine-tune.

https://github.com/linkedin/luminol/blob/42e4ab969b774ff98f902d064cb041556017f635/src/luminol/algorithms/anomaly_detector_algorithms/bitmap_detector.py#L60-L73

https://github.com/linkedin/luminol/blob/42e4ab969b774ff98f902

But as we are currently targeting JDK 8, and a new API arrived in JDK 9, it does not make sense to do this yet. The next long-term Java version 11 is scheduled for end of September 2018.
So for ELKI 0.8 it is an option to target JDK 11, and use the new API then.