The answer here is org.json4s.Extraction
-- it has a method decompose(a: Any)(implicit formats: Formats): JValue
:
def encodeJson(src: AnyRef): JValue = {
import org.json4s.{ Extraction, NoTypeHints }
import org.json4s.JsonDSL.WithDouble._
import org.json4s.jackson.Serialization
implicit val formats = Serialization.formats(NoTypeHints)
Extraction.decompose(src)
}