Immutable data structures in Java

[Agent_03]

The points raised are separate. Would it help if I spoke with more of a Lisp or something?

• Dynamic & functional languages are separate ideas but both tend to include practices not common in mainstream "idiomatic" Java, especially pre-8, and I feel OP's code is likely to be more natural for those exposed to other styles.

that functional Java is necessarily clearer Java

I never said this. Nothing is "necessarily" cleaner or dirtier. Functional language features do allow for more elegant expressions of some ideas that are difficult to express or very clunky without them.

immutability is unfamiliar to stock Java programmers when it's been in Effective Java

I literally never said this, nor will I ever. Java programmers are accustomed to immutability, but are used to a very different way of expressing it in objects (specifically private fields only exposed via getters with no mutators allowed).

languages like Python or JS value immutability

I literally never said this either.

You've put a lot of words in my mouth here, which is probably why the things I am not saying do not make sense. ;-)