There is an unsupported (read - can be removed in future without notice!) command line option with JavaFX compiler. If you run javafxc as
javafxc -XDdumpjava Test.fx
the compiler generates intermediate Java code for your JavaFX program in "./dumpjava" directory (compiler expects you to create ./dumpjava directory before invoking javafxc). This is meant to be a debugging option for JavaFX compiler developers. But, you can look at generated Java code to see what happens behind the scenes - much like C++ programmers used to look at intermediate C code and/or preprocessed code.