Running assembly fails

[MiloVentimiglia]

When I try "assembly" on the sbt I get the following error:

[error] This symbol is required by 'class scalafx.application.HostServices'.
[error] Make sure that term javafx is in your classpath and check for conflicting dependencies with -Ylog-classpath.
[error] A full rebuild may help if 'HostServices.class' was compiled against an incompatible version of .
[error] val monthlyTemp = monthGroups.map { case (m, days) =>
[error] ^
[error] one error found
[error] (compile:compileIncremental) Compilation failed
[error] Total time: 1 s, completed Apr 11, 2020 9:47:39 AM

Do you know how I might fix it?

[MarkCLewis]

I've had a bunch of students running into similar issues this semester with various classes having incompatibilities. Which one pops up depends on the details of the code. For some, reverting to Java 8 has been the fix. Others have added stuff to their build.sbt from the following link and that has fixed their problem.

https://github.com/scalafx/scalafx