When implementing a REST API, one might need to implement support for partial updates or filtering. Requests using the HTTP PATCH method commonly carry only the fields that should be updated. Similarly, filtering endpoints often filter based on the provided query parameters, while ignoring those that are omitted. In theory, this is not a complex endeavour, but, in statically typed languages, it can be surprisingly difficult to get right. While this issue is not unique to Java, the language serve...