Java 17: implementing Jackson Deserialization of Nested Generic Collections
I'm working with an scenario with Jackson while trying to deserialize a nested generic collection in Java 17. My data model consists of a `Response<T>` class, which contains a `List<Data<T>>` field. The `Data<T>` class itself has a generic type. My goal is to deserialize JSON data into this structure, but I'm working with a `JsonMappingException`. Here's the relevant part of my code: ```java import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import java.util.List; public class Main { public static void main(String[] args) { String json = "{\"data\":[{\"value\":\"test\"}]}"; ObjectMapper objectMapper = new ObjectMapper(); try { Response<Data<String>> response = objectMapper.readValue(json, objectMapper.getTypeFactory().constructParametricType(Response.class, objectMapper.getTypeFactory().constructParametricType(Data.class, String.class))); System.out.println(response); } catch (JsonProcessingException e) { e.printStackTrace(); } } } class Response<T> { private List<Data<T>> data; // Getters and Setters } class Data<T> { private T value; // Getters and Setters } ``` When I run this code, I get the following behavior: ``` com.fasterxml.jackson.databind.JsonMappingException: want to construct instance of `Response`: no suitable constructor found, can not instantiate from JSON object (need to add/enable type information?) ``` I've tried adding default constructors to both `Response` and `Data` classes, but the scenario continues. I also ensured that Jackson dependencies are correctly included in my project. Based on the behavior message, I suspect it might be related to how Jackson is handling the generic types, but I haven’t been able to find a solution. Any suggestions or examples of how to properly deserialize nested generic collections using Jackson in this context would be greatly appreciated.