This might help you As stated in the comments, the solution is to use for development the same version of Scala that you will use on the cluster.
Run spray-servlet war gives java.lang.NoClassDefFoundError: scala/collection/GenTraversableOnce$class
By : silentkriz
Date : March 29 2020, 07:55 AM
I wish this help you I ran into the very same error message with a different setup. I was using spray-client in a standalone app (no JBoss). The cause was that although I was using Spray 1.3.1 which is supposed to run on Scala 2.11 the version I was actually getting from the Maven repo (I use Maven in my project) was built against Scala 2.10. Check out the POM if you want to see for yourself.