How to add Duration to LocalDateTime for API level lower than 26

Question

I am developing an application for API level 19 (KitKat).

I have a LocalDateTime object and a Duration object. I need to add this Dur

Answer 1

The bbb answer in the comments is correct.

Currently the best option for android is ThreeTenABP. Jake Wharton explains why it's better to use this library rather than Joda-Time and ThreeTenBP in Android.