I have an old java (7, 8) app I maintain that whenever possible I move classes to Groovy as I am making other changes in them. I would probably do Kotlin, now,

I have an old java (7, 8) app I maintain that whenever possible I move classes to Groovy as I am making other changes in them. I would probably do Kotlin, now, but that wasn't an option when I started this. The amount of boilerplate removed is one big win, but moreover the more functionally oriented aspects of most anything you'd do with a for-loop in java is wonderful. And with annotations such as @CompileStatic and @TypeChecked, I am able to forgo SOME of the syntactic niceties for the compile-time binding java-comparable speed.