1. 21 of the top libraries come from Typesafe – No surprises here, Typesafe’s team is contributing the most across projects like Akka, Play, Slick, sbt and core integrations with Scala.
2. Akka is strong at #9 – This time around we saw Akka in use by 857 projects, placing it in the top 10. If you haven’t had a chance to give it a go yet, here’s a great post implementing Romeo and Juliet as… Akka Actors of course.
3. Scalatest and junit lead the charts – Similar to Java, testing is huge in Scala. Scalatest takes the top of the chart with 2,521 projects (34.4%), and junit coming in on second with 1814 projects (24.8%). Flipping seats compared to last time, where junit was at the top. Many more testing and mocking libraries found their way to top spots on the chart.
4. Logback is the most popular logging library for Scala – Coming in at #5 and in use by 16% of the projects, Logback is definitely the top pick for Scala developers. The runner up is log4j with 4.9% coming in at #36.
5. Java Guava vs Scala Guava – Being one of the most popular libraries in Java, Google Guava which ranked at #4 in the Java version of this research, is down at #37 in Scala.
6. Scalaz is the Scala Guava – The extension to Scala’s core with additional functional programming constructs is in the top at #18.
7. H2 is the most popular database on the top 100 list – Coming in at #21, H2 outranked MySQL (#33), and PostgreSQL (#50). MongoDB didn’t make the list for Scala.
8. Jetty is more popular in Scala than in Java – On the results we drew from the Java projects on GitHub, Jetty came in at #66. While originally built for Java, we’re seeing that it’s more popular in Scala coming in at #26.
5 more entries worth mentioning
#27 – Bintray-sbt – An sbt interface for publishing and resolving Bintray packages.
#60 – Paradise – A plugin for several versions of Scala compilers. It is designed to reliably work with production releases of scalac, making latest macro developments available way before they end up in future versions Scala.
#65 – Webjars – Client-side web libraries (e.g. jQuery & Bootstrap) packaged into JAR (Java Archive) files.
#81 – Shapeless – A type class and dependent type based generic programming library for Scala.
#92 – sbt-ghpages – gh-pages support for the sbt projects, allowing to host static websites on GitHub.