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So my problem is openjfx and using it on Scala-sbt project. The actual problem is JAVAFX_HOME path.

First of all I have java version 10.0.2 installed on my computer and openjfx (which I take as JavaFX) is on ubuntu repositories based on java 8jre (openjdk-8-jre is required). So when I install it needs another version of java.

But still after installing openjfx my sbt build will not open a project and gives an error

java.lang.ExceptionInInitializerError

...

Caused by: java.util.NoSuchElementException: key not found: JAVAFX_HOME

I take that this since java current version is 10 and javafx is on 8. However when I try to do

 update-alternatives --config java

and select version 8, java seems not to work on at all. The output of java --version says then:

Unrecognized option: --version

Error: Could not create the Java Virtual Machine.

Error: A fatal exception has occurred. Program will exit.

So, Is there a way to export only javafx to .bashrc similar to this:

export JAVA_HOME="$(jrunscript -e 'java.lang.System.out.println(java.lang.System.getProperty("java.home"));')"

to get JAVAFX_HOME path working or do I have to reinstall java to java 8 somehow to get javafx working correctly?

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Hjell
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1 Answers1

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Ok so sbt had errors since the build file had references to the system environemnt [system.getenv("JAVA_HOME")) in java and in sbt it was scala.sys.env("JAVA_HOME") and similarly to JAVAFX_HOME]

It is common to use JAVA_HOME system variable so this is added in linux by adding the location of java installation to the /etc/environment file. Mine was JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64". Remember to not use CLASSPATH in the environment file since it hinder the running of java files.

/etc/environment:

...
JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64"
JAVAFX_HOME="/usr/share/java/openjfx"

Remember to reboot after setting new environment variables.

Also note that update-alternatives should be done both to java and javac. And the 

java --version

does not work since in java 8 it is just 

java -version

Also in sbt you can use this line to to add 

 unmanagedJars in Compile += Attributed.blank(
   file(System.getenv("JAVA_HOME") + "/jre/lib/jfxrt.jar"))

to set current jfxrt (javaFX) file wherever that is (modify accordingly)

Hjell
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  • It's better to use a file in `/etc/profile.d` rather than `/etc/environment`. It's a bit like the difference between using `/etc/apt/sources.list.d` and `/etc/apt/sources.list`. – Chai T. Rex Sep 25 '18 at 19:37
  • What exact file? There is few of them but none of the seem to suite the purpose. Or is just to create new file and the system automatically scans it? I also assume that `export JAVA_HOME` should be used? – Hjell Sep 25 '18 at 19:54
  • Create a new `.sh` file and make it executable and, when the system reboots, it'll pick it up like `/etc/environment` is picked up. For example, here's the file that `oracle-java10-installer` adds: [/etc/profile.d/jdk.sh](https://pastebin.com/TN9BMrH6). – Chai T. Rex Sep 25 '18 at 20:12
  • You also do not need to reboot. Just sourcing the file is enough (". /etc/profile.d/javafx.sh", if it has been stored as "javafx.sh"). Please pay attention to the ".", this is the "source" command. – Marcel Waldvogel Jan 28 '20 at 17:43