JsonMappingException: Already had POJO for id
data-binding, jackson, json, rest, spring-mvc
Solution
You should use `scope` parameter when annotating the ids. Then the de-serializer would make sure the id is unique within the scope.
From Annotation Type `JsonIdentityInfo`:
Scope is used to define applicability of an Object Id: all ids must be unique within their scope; where scope is defined as combination of this value and generator type.
e.g.
@JsonIdentityInfo(generator=ObjectIdGenerators.IntSequenceGenerator.class,property="@id", scope = Account.class)
Problem
I have an error when trying to work with @JsonIdentityInfo jackson annotation. When I try to deserialize the object I get the following exception: Could not read JSON: Already had POJO for id (java.lang.Integer) [1] (through reference chain: eu.cobiz.web.domain.Site["operators"]->eu.yavix.web.domain.Account["image"]->eu.cobiz.web.domain.Image["@Image"]);nested exception is com.fasterxml.jackson.databind.JsonMappingException: Already had POJO for id (java.lang.Integer) [1] (through reference chain: eu.yavix.web.domain.Site["operators"]->eu.cobiz.web.domain.Account["image"]->eu.cobiz.web.domain.Image["@Image"]) The JSON I am trying to deserialize looks like: ``` { "@Site": 1, "siteId": 1, "name": "0", "address": { "@Address": 2, "addressId": 4, "number": "22" }, "operators": [ { "accountId": 1, "email": "user982701361@yavix.eu", "image": { "@Image": 1, "imageId": 1, "uri": "http://icons.iconarchive.com/icons/deleket/purple-monsters/128/Alien-awake-icon.png" } }, { "accountId": 2, "email": "user174967957@yavix.eu", "image": { "@Image": 2, "imageId": 2, "uri": "http://icons.iconarchive.com/icons/deleket/purple-monsters/128/Alien-awake-icon.png" } } ] } ``` My domain object is annotated with ``` @JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class, property = "@Image") ``` The problem arises on @Id annotation since if I remove the annotation the problem disappears (as I did for account) but on my understanding the new feature is useful for cyclic dependencies which is useful for me in other scenarios. There shouldn't be a conflict between the 2 images since they are different objects. How can I solve this or what is the problem?