I'd say the bigger threats to Scala in terms of adoption are potentially Kotlin (and the strong JetBrains tooling that will inevitably come with it), typed Cloj

I'd say the bigger threats to Scala in terms of adoption are potentially Kotlin (and the strong JetBrains tooling that will inevitably come with it), typed Clojure, and Haskell. Otherwise, Java 8 is not a game changer for the simple fact that the enterprise moves at a snail's pace in terms of adoption. Teams with the flexibility to switch from pre-Java 8 to Java 8 will likely also have the freedom to choose an alternate JVM language, or perhaps even Haskell if they're not tied to the JVM.