Only an open protocol like Matrix will end this race of platforms/apps for users and their data. WhatsApp or iMessage is not a real decision from a user perspective...
Thank you for pointing this out. I will think about it again and discuss with our team.
In JavaScript there are no interfaces but in Java I remember that I have seen this quite often.
These coding conventions were developed as side-product to our lecture “Software Architecture for Distributed Embedded Systems” held by Prof. Steinhorst at TUM.