1) You don't have to do that, Scala doesn't enforce the folder/package hierarchy that Java does. Moreover, you can use any folder hierarchy you want. 2) Compi

1) You don't have to do that, Scala doesn't enforce the folder/package hierarchy that Java does. Moreover, you can use any folder hierarchy you want. 2) Compiling Scala is slower than Java (sometimes much slower) but that's not the frameworks' fault. scalac is just slow, though getting better. 3) This does exist. In fact, it's built into the language. You can also use "sbt console" to load a REPL with your entire project in the classpath. 4) As the other reply said, type annotations aren't required. In that light, Scala's syntax for type annotations makes sense.