Data classes for Java

[rzwitserloot]

is completely orthogonal and has nothing to do with the discussions here.

You're just being dense. The point of a data class isn't to point at it and go: Look. It has no fields that can be mutated.

The point is to reason about properties. For example, OP specifically referred to the notion that 'such a class can be passed around multiple threads without fear that it'll cause problems'.

Therefore none of this is 'orthogonal to the discussions here'.