intellij idea - What is the _root_ package in Scala?

Question

I'm using IntelliJ IDEA with the Scala plugin. If I reference HashMap in code, and then use Alt-Enter to add the import, the package gets imported as:

_root_.scala.collection.immutable.HashMap

What's the root part of this? It seems to work with and without it.

Answer 1

It has to do scala imports being relative - _root_ gives you a way to specify an absolute package name. See the Scala Wiki