I'm talking about what it compiles down to. Kotlin routinely generates bytecode that uses Java idioms either for its own ABI or in addition to it. So yeah, if s

I'm talking about what it compiles down to. Kotlin routinely generates bytecode that uses Java idioms either for its own ABI or in addition to it. So yeah, if some builder classes were produced behind the scenes for an immutable data class, why not, that'd be cool. You could always disable that feature with a flag if for some reason the bytecode size was an issue.