Jackson deserialization fails (Spring Boot 2.5)

After migrating to Spring Boot 2.5, some of my controller tests failed with the following warning:

RepositoryRestMvcConfiguration$ResourceSupportHttpMessageConverter Failed to evaluate Jackson deserialization for type [[simple type, class org.springframework.data.rest.webmvc.PersistentEntityResource]]: java.lang.NullPointerException: Cannot invoke “org.springframework.data.util.TypeInformation.getActualType()” because “propertyType” is null

As far as I can tell, this only happens to tests where I place an URI reference in payloads, e.g.: http://localhost/entity/foobar. To me it looks like Spring Data Rest can’t resolve the entity thats referenced by the URI. Any ideas what could be the issue?

Test logs

10:58:23.048 [main] WARN RepositoryRestMvcConfiguration$ResourceSupportHttpMessageConverter Failed to evaluate Jackson deserialization for type [[simple type, class org.springframework.data.rest.webmvc.PersistentEntityResource]]: java.lang.NullPointerException: Cannot invoke "org.springframework.data.util.TypeInformation.getActualType()" because "propertyType" is null

MockHttpServletRequest:
      HTTP Method = POST
      Request URI = /follows
       Parameters = {}
          Headers = [Content-Type:"application/hal+json;charset=UTF-8", Content-Length:"66"]
             Body = {"followee":"http://localhost/athletes/paul","status":"REQUESTED"}
    Session Attrs = {}

Handler:
             Type = org.springframework.data.rest.webmvc.RepositoryEntityController
           Method = org.springframework.data.rest.webmvc.RepositoryEntityController#postCollectionResource(RootResourceInformation, PersistentEntityResource, PersistentEntityResourceAssembler, String)

Async:
    Async started = false
     Async result = null

Resolved Exception:
             Type = org.springframework.http.converter.HttpMessageNotReadableException

ModelAndView:
        View name = null
             View = null
            Model = null

FlashMap:
       Attributes = null

MockHttpServletResponse:
           Status = 400
    Error message = null
          Headers = [Vary:"Origin", "Access-Control-Request-Method", "Access-Control-Request-Headers", Content-Type:"application/vnd.wdb.problem+json;charset=UTF-8", X-Content-Type-Options:"nosniff", X-XSS-Protection:"1; mode=block", Cache-Control:"no-cache, no-store, max-age=0, must-revalidate", Pragma:"no-cache", Expires:"0", X-Frame-Options:"DENY"]
     Content type = application/vnd.wdb.problem+json;charset=UTF-8
             Body = {"status":400,"title":"Bad Request","detail":"Bad Request","instance":"http://localhost/follows","type":"https://developer.mozilla.org/docs/Web/HTTP/Status/400","invalid-params":[]}
    Forwarded URL = null
   Redirected URL = null
          Cookies = []

java.lang.AssertionError: Status expected:<201> but was:<400>
Expected :201
Actual   :400

Possible duplicate of #2015

[sullrich84]

This issue seems to be fixed when updating to Spring Boot 2.5.3.

[dineshbhagat]

here it is: https://github.com/JanStureNielsen/so-68011276, https://stackoverflow.com/q/68011276/2987755