[java] Can I import javafx classes for using GUI methods here in Sololearn's Code Playground?

Question

... or only works for text-based programs?

Answer 1

No, Java GUI frameworks don't work at the playground.

Answer 2

JavaFX is included in the jdk and the jre.
IDE compiles the code and then runs it (needs jdk to compile and jre to run), same as you would do via console.
Just install the jdk and an IDE you like and you've got everything you need.