I tried to compile the JavaFX HelloWorld demo form Oracle on Ubuntu 16.04.3 LTS with OpenJDK 9, but it did not work:
$ javac -version
javac 9-internal
$ javac HelloWorld.java
HelloWorld.java:3: error: package javafx.application does not exist
...
I can't find an OpenJFX package for Java 9 in the package manager. The one that exists only works for OpenJDK 8 (I tried installing it anyway, but it did not help):
$ apt-cache search openjfx
...
openjfx - JavaFX/OpenJFX 8 - Rich client application platform for Java
...
Do I have to install JavaFX from source to compile JavaFX applications with OpenJDK 9 on Ubuntu?