Dropwizard returns 400 on valid GET

Question

I'm developing a Dropwizard app and am facing a strange bug on a GET request after I have included mongojack.

I have a simple GET query with the ID as a path parameter. It worked before I included mongojack and added two annotations to my entity:

public class Bill {
    @javax.persistence.Id @org.mongojack.ObjectId
    private String id;

    @javax.persistence.Id @org.mongojack.ObjectId
    public String getId() { return id; }

    //...
}

What puzzles me most is that the request is actually accepted. When I debug, I can step into the method. The entity is loaded from MongoDB into memory and looks fine. So I suspect that this might actually be serialization issue, but currently I'm stuck. Any ideas?

Update

Seems to be a known mongojack issue: https://github.com/devbliss/mongojack/issues/26. Later I want to use custom DTOs without ObjectIds for my GETs anyway, so this shouldn't be relevant anymore. What I still don't understand is why Dropwizard maps this to a 400 response...

Answer 1

What I still don't understand is why Dropwizard maps this to a 400 response

Dropwizard, via Jackson, generates JSON using all the getters (or @JsonProperty annotated fields/methods) as you know. If any exception occurs on getters (or setters on deserialization) dropwizard automatically returns 400 Bad Request.

I guess that makes sense since it expects simple POJO DTOs with dumb getters and setters.