Is it possible that it's skewed because Gradle (build system used for pretty much all Android applications and many standard Java applications) uses Groovy as it's configuration file language? Causing a misdetection (e.g. most Android Kotlin projects would show up as Groovy as well) ?

It always blows my mind when everyone seems to forget Groovy. Especially since Kotlin is very very similar (well, syntactically anyway). The difference of course is that Groovy has full Spring support, Gradle, Spock etc.

Maybe Gradle is the 'killer app' that keeps Groovy popular? I've heard from people with tricky build tool requirements that it's one of the best options out there.

I see Groovy in 3 places: Gradle files (a Kotlin alternative is coming), Jenkins pipeline build scripts, and the Spock testing framework.

I don't have a good read on how popular Grails is anymore. I liked it a lot in the past but I don't need it anymore with Kotlin and Spring Boot.

> Gradle files (a Kotlin alternative is coming)

Gradle's been able to use Kotlin for build files since Gradle 3.0 which was released last year.

For Jenkins, only a subset of Apache Groovy can be used. None of the functional methods will work when used.

Grails 2.x is still around, but virtually no-one's converting their projects to version 3, or starting new Grails projects in version 3.

Groovy development has come to a standstill, and even contributions from outside developers just sit there, such as the new Antlr 4-based parser which someone contributed a whole year ago.

Kotlin has its own build system - Kobalt.

We've stuck with Grails for a few years now and I still prefer it over vanilla Spring Boot. Things like JSON views and GORM are still really nice to have.

groovy is great. It doesn't have much marketing behind it, so it's seems to be a bit of a quiet achiever. But for dsl makin', groovy is such a good language.!

We use Groovy in production, working with SQL, Transactions or JSON is much easier than Java. Meta programming and Traits are other advantages. The biggest advantage is that it is so similar to Java code, that any Java developer can pick it up and understand it immediately.

We still love and use Java a lot and they both complement each other very well.

> it is so similar to Java code, that any Java developer can pick it up

Perhaps Java 7, but Apache Groovy doesn't have the lambda syntax from Java 8. Development on Groovy has stagnated -- someone even contributed a fully working Antlr-4 based parser to replace their outdated Antlr-2 based one last year, but it's been sitting in their development repository at Github going nowhere ever since.

We use Groovy at my work in a majority of our projects as well. I love traits and some of the other shortcuts and I don't feel like I'm too far away from Java that I couldn't work in it immediately.

I should perhaps check it out again. It's been years since I've used it, but did enjoy it when I did.

Groovy deserves better. But its tight couple with JVM eliminate the possibility of native or JS.

Groovy has the best testing framework that I have ever used, Spock. When I write .Net code I really miss it, there is nothing that I found as powerful, even using F#.

What do you miss that's not in F#? Legitimately curious, since F# is the language I miss (or wish to use, I suppose) the most at the moment.

It's the overall experience that is great. Creating a stub or a mock with just: IMyService myService = Stub() // Mock()

Returning something from the stub:

myService.getData() >> data

verifying the returned value without explicit assert:

result == expected (This will show a very informative error in case of mismatch and gives you the ability to see the differences in a diff style window)

Interaction based testing is a breeze with this:

3 * myService.getData()

1 * myOtherService.getData()

And finally the data driven testing is the most natural that I have ever seen. You just need to literally create a table and use the column name in your test or even in your test title. Writing tests becomes a joy with Spock.

In F# I have looked at expecto, fsunit and some other library, but I can't find anything remotely equivalent.

The killer feature of Groovy is Spock tests. It really shines there.

sincerest form of flattery?

http://spekframework.org

Kotlin-based Spek uses standard lambdas for defining specs, whereas Spock digs into the Apache Groovy parser to change the meaning of labels in the syntax, as well as uses operator overloading. One's elegantly functional, the other's a cheap hack.