EDIT: or to phrase it better, what is missing or hard to do that you feel has the biggest influence (some things are possible, but just way more complicated)? I don't have enough FP experience myself to judge that.
Can you write maintainable, sane, and performant C++ code that leverages immutable data structures, guarantees referential transparency, and eschews mutable state?
Certainly there are languages which don't support FP approaches well. But lack of utility is not the same as impossibility. If nothing else the exercise ("How far can you take FP in Java?") will teach you all kinds of things.
> Certainly there are languages which don't support FP approaches well. But lack of utility is not the same as impossibility. If nothing else the exercise ("How far can you take FP in Java?") will teach you all kinds of things.
My mistake then. I agree that seeing how far you can take FP in Java is a useful exercise.