On replacing JavaConversions with JavaConverters

You need to add the asScala method:

import scala.collection.JavaConverters._

for ((k,v) <- environmentVars.asScala) println(s"key: $k, value: $v")

Since Scala 2.13, this is now CollectionConverters:

import scala.jdk.CollectionConverters._

for ((k,v) <- environmentVars.asScala) println(s"key: $k, value: $v")