If you are predominately working with immutable data, you are essentially doing functional programming. In which case you'd be much better off in a functional-f

If you are predominately working with immutable data, you are essentially doing functional programming. In which case you'd be much better off in a functional-first language. Using Scala entirely for FP has not worked out well in practice. Even the authors of "Functional programming in Scala" eventually abandoned it for Haskell. Scala has certainly raised awareness of FP, which is a big positive in its favour and the support it does have for FP is an improvement over Java.