Java 11 - implementing JSON Parsing using Jackson with Nested Objects and Null Values
I recently switched to I can't seem to get I'm stuck on something that should probably be simple... I'm working with an scenario with parsing JSON into a Java object using the Jackson library. I'm using Java 11 and Jackson version 2.12.3. My JSON structure includes nested objects, and some of the fields can be null. When I attempt to deserialize the JSON string, I encounter the following behavior: ``` com.fasterxml.jackson.databind.JsonMappingException: want to construct instance of `com.example.User` (no Creators, like default constructor, exist): want to deserialize from Object value (no delegate- or property-based creator) ``` Here's the JSON I'm trying to parse: ```json { "id": 1, "name": "John Doe", "email": null, "address": { "street": "123 Elm St", "city": "Anytown", "zipcode": null } } ``` And here are my Java classes: ```java public class User { private int id; private String name; private String email; private Address address; // Getters and Setters } public class Address { private String street; private String city; private String zipcode; // Getters and Setters } ``` I have a default constructor in both classes, and I've also verified that the getters and setters are properly defined. However, the presence of null values in the JSON seems to be causing the deserialization to unexpected result. I've tried using annotations like `@JsonInclude(JsonInclude.Include.NON_NULL)` on the fields, but it didn't resolve the scenario. I've also attempted to register a custom deserializer, but that added more complexity without yielding results. Can anyone provide insights into how to properly configure Jackson for this scenario with nested objects and nulls? Are there any best practices I might be missing that could help avoid this deserialization question? How would you solve this? Has anyone else encountered this? What am I doing wrong?