# @MappingTarget updates: nested objects and collections are changed in place


--- patch only the city and the roles ---
address: email=Asha.Mehta@Example.com, nickname=null, roles=[USER, ADMIN], address=12 Park Road/Mumbai/411001
same Address instance as before? true   <- AddressMapper.update was called on it
same roles Set instance as before? true  <- cleared and refilled, not replaced
another holder of the old roles Set now sees: [AUDITOR]

--- an immutable collection on the target ---
patching roles on a Set.of(...) target threw: java.lang.UnsupportedOperationException