I wouldnt use hxjava - haxe jvm works and, imo, is better (and supercededs it)
This was the case in a very old version of haxeui (like a v1, or maybe even a v0), haxeui now supports multiple backends: https://github.com/haxeui/haxeui-core
There is a really interesting one here: https://lib.haxe.org/p/hx-ios-uikit/