Why does the Scala IntelliJ plugin take so long to start my application?

Question

I go back and forth between Eclipse and IntelliJ for Scala development. IntelliJ's code-complete, refactoring and error-highlighting are all better (in my experience) but I end up going back to Eclipse because whenever I run a Scala application in IntelliJ, it goes through this very long compilation process that Eclipse somehow avoids.

I can see the status bar whiz by as it loads each individual class and then runs them through several phases. I know that scalac is slow in general, but it's much quicker to use the command line or Eclipse than it is to use IntelliJ.

Is anyone else seeing this behavior? Will turning on fsc support make a big difference?

Answer 1

Either use the IDEA SBT plugin to delegate compilation to SBT, or enable use of Fast Scala Compiler (FSC) under Settings → Compiler → Scala.

Otherwise IntelliJ starts and stops a scalac process to compile each batch of files, and this has some overhead.