Smalltalk is exactly like that - other objects' state is only mutable through explicit message passing. It's also widely considered the penultimate pure OO language.

> Pretty much all of the OO languages are walking back OO features

About the only feature I can think of for which this is somewhat true is inheritance, and that's because we realized that aggregation is often a better model, and can be easily supported by the language to be no more verbose. But it doesn't fundamentally change OO - it was never about inheritance first and foremost; I mean, prototype-based OO doesn't even have that conceptually.

> and trying to add type classes (contracts)

In most OO languages, these typically naturally evolve out of interfaces.

> functional pieces, mapping and filtering a la linear data transformations.

This is not contradictory to OO in any way. Again, Smalltalk has had "select" (filter) and "collect" (map) from the get go.

Lombok makes immutable data classes trivial. Improved interface support for default methods make it possible to largely ignore OO if you don't want it.

FP is mostly a community effort at this point, but solid. Java Streams are decent for basic stuff like map/filter but RXJava is extremely powerful if you want the complexity it comes with. Vavr is nice for adding more FP types too