I am using Windows 10 64-bit and eclipse java 2019-06.I have installed jdk 12.0.2 and jre 8u221. I have set environment system path in environment variable to C:\Program Files\Java\jdk-12.0.2\bin.I can easily compile and run java file in windows command prompt. I can not import javafx.
I have used e(fx)clipse (javafx1 in the following picture). I have also tried adding jfxswt.jar into external library(javafx2 in the following picture).