I have thoroughly enjoyed that Hickey talk, but I think he has a very system-oriented view/take - which is very important and shows his experience - but it is also common to have control over the whole universe for our program.
In the interconnected system view, data schemas can change without notice, and the program should be backwards and forwards compatible to a reasonable degree to avoid being brittle.
This is not a problem when we control the whole universe.
I find that Haskell-esque type systems (strongly typed with frequent use of algebraic data types to represent every possible state in _that_ universe) work better for the latter, but are not the best fit for the former, and they often have to add some escape hatches at the boundaries.
Java itself is in a weird cross of this two - it has a reasonably strong type system nowadays, but it’s also a very dynamic runtime where one can easily create their own class at runtime and load it, reflect on it, etc.
So all in all — are you making that Car as part of your universe where you control everything, and it won’t change in unexpected ways? Make a record, potentially with nullable/Optional/Maybe types for the fields, if that makes sense.
If it represents some outside data that you don’t control, then you might only care about a subset of the fields: create a record type for that subset and use a converter from e.g. json to that record type, and the converter will save you from new fields. If everything is important then your best bet is basically what Clojure/JSONObject/etc do, just have a String-keyed map.
(Note: structural types can help here, and I believe OCaml has row polymorphism?)
In the interconnected system view, data schemas can change without notice, and the program should be backwards and forwards compatible to a reasonable degree to avoid being brittle.
This is not a problem when we control the whole universe.
I find that Haskell-esque type systems (strongly typed with frequent use of algebraic data types to represent every possible state in _that_ universe) work better for the latter, but are not the best fit for the former, and they often have to add some escape hatches at the boundaries.
Java itself is in a weird cross of this two - it has a reasonably strong type system nowadays, but it’s also a very dynamic runtime where one can easily create their own class at runtime and load it, reflect on it, etc.
So all in all — are you making that Car as part of your universe where you control everything, and it won’t change in unexpected ways? Make a record, potentially with nullable/Optional/Maybe types for the fields, if that makes sense.
If it represents some outside data that you don’t control, then you might only care about a subset of the fields: create a record type for that subset and use a converter from e.g. json to that record type, and the converter will save you from new fields. If everything is important then your best bet is basically what Clojure/JSONObject/etc do, just have a String-keyed map.
(Note: structural types can help here, and I believe OCaml has row polymorphism?)