Concurrency issue with ObjectMapper on RESTful http call

[ShawnTuatara]

I had originally asked about this issue on the Jackson side of things but thought it relevant to post this here as well.

FasterXML/jackson-databind#604

There was a comment on my original issue about why the canDeserialize() is being called instead of readValue() as well as if the ObjectMapper is being re-used. I am hoping that someone can take a look at how the spring-boot project is interacting with the ObjectMapper on the deserializing the json http request to see if there is any issues that would cause the problem I am having.

[philwebb]

AFAICT AbstractJackson2HttpMessageConverter is the only class that calls ObjectMapper.canDeserialize and it uses a singleton ObjectMapper. Do you have a sample project that you can share? I especially interested in why DeserializerCache._findCachedDeserializer wouldn't get a hit and what JavaType is being requested.

/cc @rstoyanchev in case he has seen this in MVC before.

[ShawnTuatara]

I can't share this specific project but I think it might be related to the @RequestBody annotated parameter that I am using. Specifically it is:

    @RequestMapping(method = RequestMethod.POST)
    @ResponseStatus(HttpStatus.CREATED)
    public Map<String, List<EventId>> addEvent(@RequestBody Map<String, List<RestEventCreation>> wrappedEvents)

I read somewhere in the comments of the DeserializerCache that the Map deserializer doesn't get cached. I am going to try if I can convert that parameter type to be a class that encapsulates the Map definition that I have.

[ShawnTuatara]

That resolved it. My method signature is now:

    @RequestMapping(method = RequestMethod.POST)
    @ResponseStatus(HttpStatus.CREATED)
    public Map<String, List<EventId>> addEvent(@RequestBody RestEventCreationWrapper restEventCreation, Integrator integrator)

@cowtowncoder any reason why Jackson doesn't allow caching of the Map type?

[cowtowncoder]

@ShawnTuatara I consider it a flaw, and will be fixing it for Jackson 2.4.4. Back in the day construction of Map deserializers was a much lighter operation, so assumption was that it'd be wasteful to cache. But that is definitely not the case any more. Thank you for reporting this!

[philwebb]

@ShawnTuatara Thanks for the report. I'll close this one here and we'll wait for the Jackson 2.4.4 release.