I've downloaded OpenJDK 8 today via sudo apt-get install openjdk-8-jdk
and it seems like JavaFX is not included in it.
> java -version
openjdk version "1.8.0_66-internal"
OpenJDK Runtime Environment (build 1.8.0_66-internal-b17)
OpenJDK Server VM (build 25.66-b17, mixed mode)
I've installed E(fx)clipse in latest Eclipse (Eclipse Mars) too, but I'm still getting message javafx couldn't be resolved.