Ultimately, you don't need to learn every single Scala feature to get started using it. As a Java developer you only need to learn a few differences before you

Ultimately, you don't need to learn every single Scala feature to get started using it. As a Java developer you only need to learn a few differences before you can start using it as a "Java with better syntax" (var/val/def, static/object, Object/AnyRef, void/Unit, interface/trait, <>/[], []/()), learning the Scalaisms later on as you go. You don't need Scalaz to write Scala code. You can even ignore most of the standard library while you're starting out, and use the Java equivalents. SBT might seem pointless at first, but the same thing applies there. You don't need to use it, plugins for Maven and Gradle are available. But once you do switch, you'll see how much nicer it is.