Rustam Mehmandarov: Unknown JSON fields in Java REST clients: JSON-B, Jackson, Quarkus, and Spring Boot (opens in new tab)

You call an API with the MicroProfile REST Client, map the response onto a small DTO, and one day the API starts returning a few extra fields you never asked for. Does your client shrug and carry on, or does it blow up with a deserialization error? The honest answer is “it depends on your JSON provider” – and the defaults are not the same across the board. Let’s pin down what actually happens, and point to the spec or docs for each case. Introduction Imagine a small REST client. You are consu...