I just had to pick up and build a UI product in java recently and picked up javafx for the first time. With Kotlin, I actually found it while using my the standard you builder to be quite intuitive and sorta dynamic enough to make development snappy. Definitely the best attempt at GUIs for java, but sad that only smaller shops are actually investing any real effort into the space. Oh and java native + javafx is a pain in the ass until I discovered Bellsoft NDK, which made building a binary from source 100% so much easier.