If you have more than 2 levels of nested null-checks I would wager you are doing something fishy. You should probably go with mapstruct or similar libs (which are absolutely cool and a must for data conversions).
On my fishy scale, requiring translation between different data models would by pretty high up. And how would it help anyways? Absence can be a perfectly valid state and alternative representations of absence like scala's Option seem pointlessly ceremonous once you've worked with a syntax that does not completely suck at dealing with null.
