The way this problems change in Scala is not by using the parallel collections library, but by using Akka straight up, or using Spark.

Akka is an actor system framework, so it's extremely well suited for this problem.

Spark can process tremendous amounts of data in parallel, even over hundreds of machines if you really have the iron, and works just as well with just one machine.

You can technically use them both from Java, but being natively Scala libraries, you are really better off switching to Scala if you are going to use them.