RuntimeException: Package jdk.internal.jimage.decompressor in module jrt.fs and module java.base

$JAVA_HOME/lib/jrt-fs.jar contains a copy of the "jrt" file system provider compiled to JDK 8. It's for tools such as IDEs that run on JDK 8 but need to access a JDK 9 run-time image.

From the exception then it does appear that this JAR file, or maybe $JAVA_HOME/lib, has been put on the module path in error. JAR files that do no contain a module-info.class in the top-level directory are treated as automatic modules so this is why the exception has "module jrt.fs" in the message. The exception basically just means that you've ended up with two modules containing the jdk.internal.jimage.decompressor package (and many other packages) due to putting jrt-fs.jar on the module path.

I had the same issue on Manjaro Linux, while it was working fine on windows. Looking at the differences it became clear that the javafx 11 package installs into /lib/jvm/java-11-openjdk/lib, which I then set as PATH_TO_FX. This seems to be the issue, because jrt-fs.jar is in the same folder.

I moved all files from fx to a separate folder and then set that as PATH_TO_FX. Now it works fine.

I got the same error under Arch Linux. The package java-openjfx installs its libraries into the lib directory of the openjdk, which seems to cause problems. I found a workaround by adding not the whole lib directory but only the needed libraries instead.

In project structure > Libraries > + > Java > /usr/lib/jvm/default/lib > select needed libraries (holding ctrl) should look something like this

Then in Run Configurations set the VM Options accordingly

    --module-path /usr/lib/jvm/java-14-openjdk/lib/javafx.base.jar:/usr/lib/jvm/java-14-openjdk/lib/javafx.controls.jar:/usr/lib/jvm/java-14-openjdk/lib/javafx.graphics.jar --add-modules=javafx.controls

For my project it was enough to only add controls as module but the path to base and graphics were required to get it to run.