How do I get Java FX running with OpenJDK 8 on Ubuntu 18.04.2 LTS?

Question

When trying to compile an JavaFX application in the environment:

java -version
openjdk version "1.8.0_212"
OpenJDK Runtime Environment (build 1.8.0_212-8u212-b03-0ubuntu1.18.04.1-b03)
OpenJDK 64-Bit Server VM (build 25.212-b03, mixed mode)

cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=18.04
DISTRIB_CODENAME=bionic
DISTRIB_DESCRIPTION="Ubuntu 18.04.2 LTS"

I get the error-message:

cannot access javafx.event.EventHandler
[ERROR]   class file for javafx.event.EventHandler not found

I tried to find a solution by following these links:

• how to add javafx dependencies in maven with java 10
• https://mvnrepository.com/artifact/org.openjfx/javafx/11
• Maven project with JavaFX (with jar file in `lib`)
• https://github.com/javafx-maven-plugin/javafx-maven-plugin
• https://askubuntu.com/questions/1091157/javafx-missing-ubuntu-18-04
• https://unix.stackexchange.com/questions/505628/add-openjfx-class-path-in-debian-for-java11
• https://askubuntu.com/questions/609951/javafx-is-not-on-the-default-classpath-even-with-oracle-jdk-1-8
• Why is JavaFX is not included in OpenJDK 8 on Ubuntu Wily (15.10)?
• http://can4eve.bitplan.com/index.php/JavaFX

The most promising actions where to

1. install openjfx with apt install openjfx
2. set the JAVA_HOME environment variable to /usr/lib/jvm/java-8-openjdk-amd64

But the error persists.

What needs to be done to get OpenJDK 8 and JavaFX working on Ubuntu 18.04.2 LTS?

Solution 1

The hint from

https://github.com/JabRef/help.jabref.org/issues/204

helped. The commands:

apt purge openjfx
apt install openjfx=8u161-b12-1ubuntu2 libopenjfx-jni=8u161-b12-1ubuntu2 libopenjfx-java=8u161-b12-1ubuntu2
apt-mark hold openjfx libopenjfx-jni libopenjfx-java

fixed the problem. Many thanks to https://github.com/Druidefix for this. (If you'd like to answer this yourself I'll happily delete my own answer ...)

Solution 2

What I did was build it from source. The instructions here on the OpenJDK wiki worked for me. Once I built it, I had to put the jars in the right place, like this other stackoverflow post talked about.

cd build/sdk/
sudo cp -R rt/lib /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/
sudo cp ./lib/ant-javafx.jar /usr/lib/jvm/java-8-openjdk-amd64/lib/
sudo cp ./lib/javafx-mx.jar /usr/lib/jvm/java-8-openjdk-amd64/lib/

After that I was able to compile my project!