I have my share of grievances against Scala, but the difference in collection libraries only feels painful if your app can't tolerate the performance hit of re-

I have my share of grievances against Scala, but the difference in collection libraries only feels painful if your app can't tolerate the performance hit of re-copying a collection (which to be fair does sometimes occur on hot codepaths). Otherwise it's a simple .toScala or .toJava call away. Also arrays are one place where Scala and Java do happen to share the same collection.