I'd be interested to hear how you get on with Spark. If you try it at all that is.
Spark wrote:A micro framework for creating web applications in Kotlin and Java 8 with minimal effort
Tag lines such as this make me nervous. In my previous experience of similarly pitched products it has turned out to be really handy at first getting set up very quickly, but frustration emerges when you want to do something outside of the prescribed 'modus operandi'. Then things get really hacky really quickly and the initial benefits are soon lost.