In order to implement all the Scala language magic the generated byte code is sometimes far away from what the equivalent Java code byte code would look like.

In order to implement all the Scala language magic the generated byte code is sometimes far away from what the equivalent Java code byte code would look like. This isn't a problem for most people but it is an issue for anyone who uses stuff like byte code instrumentation - take a look at this issue for example: https://github.com/puniverse/quasar/issues/45 https://github.com/puniverse/quasar/issues/45 It's not a criticism of Scala (the language is just a LOT richer so has to cater for more sophistication). But the difference matters to me which is why I prefer Kotlin over Scala and I'm prepared to miss out on some of that sweet Scala magic.