If you stick to the same kind of subset in Scala, then compilation isn't that much worse than Java, IME. It's only when you're using a lot of implicits and/or a lot of type inference that compile times go through the roof.

(and FWIW I'd say that 2000+ classes - that's what, 600KLOC? - implies a project that should be split up with clear boundaries (i.e. separate release cycles, documented public APIs between them), if only for developer comprehensibility. How big is a Java project that provides the same amount of functionality, and how long does it take to compile? Crikey, 2000 classes...)

Some companies, like Twitter and Facebook, are doing this development pattern of mono repo... So even if there are architectural lines to be found, they are eschewing that in favor of keeping versions and APIs closer together.

I can't say I understand that strategy completely but I have also never worked on machinery the size and complexity of Facebook or Twitter.

As a point of reference, compiling ~200 Scala classes at a time would take ~2.5 minutes on average. At my last job, compiling >2000 Java classes took about 10-15 seconds with an ant script doing a top-down build. Unfortunately I don't remember LOC, but I don't remember the average Scala file being overly large at my Scala job, or the average Java file being unusually short at my Java job.

> Unfortunately I don't remember LOC, but I don't remember the average Scala file being overly large at my Scala job, or the average Java file being unusually short at my Java job.

LOC isn't what should count though - there are cases where 1 line of Scala offers functionality that would take 10 or more lines of Java to implement.

> As a point of reference, compiling ~200 Scala classes at a time would take ~2.5 minutes on average.

Odd... I just did a full compile of a Scala project I work on which has:

- 259 source files

- Contains dozens of macros[1]

- Results in 2097 classes (includes companion objects and anonymous types)

And it took 75 seconds on my laptop. As I mentioned in another reply, doing a full recompile is rarely needed but was done now to provide quantified metrics.

1 - http://docs.scala-lang.org/overviews/macros/overview.html

In Java, I compile around 250 classes in about 6 seconds on my laptop. It results in around 250 class files being generated because no filea for anonymous inner classes are created from the lambdas in the code. I don't need a full recompile either. An incremental compile in Java is measured in milliseconds. IntelliJ is usable to its fullest instead of being a fancy editor that just autocompletes and jumps to symbol definitions.

You may not be using all of scala's language features. I'm using java's features to the fullest. I compile in 6 seconds. You compile in 75 seconds. You may still prefer that trade off. After working with thousands of scala files (you have 259 source files? That's cute! I wish I could pinch your cheeks!) where a 75 second compile sounds like a fail-fast error, I think I will live happier with what Java 8 has, limited and warted though it may be.

You have no idea my background, how I use Scala, and assume that the small project I reference is the only project I _could_ reference. It was chosen due to being near the size of the situation you describe as "compiling ~200 Scala classes at a time would take ~2.5 minutes."

Being a condescending asshole doesn't help you communicate with others. Frankly, it strengthens my opinion that you don't know how to organize a medium-sized project, since being able to do so obviates requiring to compile 2000+ files for each build _in any language_.

Question - I don't know much about Scala - how often does one need to do a full build? I am talking regular development cycle, ie make a change, save/compile, check if it works etc. I mean typically a compiled language will have some 'incremental compile' to compile just the file you edited. Does that work with Scala?

> Question - I don't know much about Scala - how often does one need to do a full build?

Not often at all.

> I am talking regular development cycle, ie make a change, save/compile, check if it works etc.

sbt[1] supports incremental compilation and projects such as Play[2] leverage this to support "on-the-fly" recompilation while the container remains running.

1 - http://www.scala-sbt.org/0.13/docs/Understanding-Recompilati...

2 - https://www.playframework.com

Way more than 2000 classes? How many LOC is that?

How much time did it take to compile, and how much time does the same 2000+ classes take to compile in Java?

Scala's compilation time is not an excuse to write ugly hard to maintain code in Java 8. If you don't like Scala compilation time then write Java 8 but keep it idiomatic and easy to read don't drag parts of Scala into it that don't fit.

Still at that company, and still enduring long compile times.