It's only very special circumstances where my POD types do not consist entirely of `final` fields. Though I usually skip defensive copying within PODs... One should know better than to trust values from random places. So I defensively copy at use time instead if I want to modify it.

Kotlin, Java's superior offspring, is even better, as the use of data classes provides an automatic implementation of a `copy` command. (Scala does too, but Scala also explodes when I look at it, so, enh.)