Setting target JVM in SBT

You can specify compiler options in the project definition:

javacOptions ++= Seq("-source", "1.8", "-target", "1.8") 

you have to add(in your build.sbt file):

scalacOptions += "-target:jvm-1.8"

otherwise it won't work.

As suggested by others in comments, the current sbt version (1.0, 0.13.15) uses the following notation for setting source and target JVMs.

javacOptions ++= Seq("-source", "1.8", "-target", "1.8")