No, it applies for local variables as well: http://stackoverflow.com/questions/7423028/java-local-variab...

I still don't understand why you consider having a compiler-enforced restriction on mutation worse than letting readers figure out what was the developer's intent.

In Java, the only "downside" is having to add "final" as a modifier, which is negligible.

In Scala, the alternative is to declare that variable as "var" instead of "val". When would you ever choose var over val if your object isn't supposed to mutate?