@voddan: Close enough on the data structure and bingo on the JSON updates (transformed to

Map

). I like the idea of using reflection only once on initialization -- that sounds promising. Thinking about implementation: each type could use reflection to create a lambda for each of its properties to (recursively) convert from the JSON value to the property type. Updates would then use the pre-created lambda rather than reflection for the type conversion. Then each type would call its own

copy

function with the result of calling every property update lambda and the update

Map

. Is that what you had in mind?