[jax-rs-spec users] [jsr339-experts] ContainerResponseContext and getMediaType

From: Sergey Beryozkin <>
Date: Wed, 13 Mar 2013 14:01:46 +0000


I have a doubt about ContainerResponseContext#getMediaType method which
returns the media type of the entity.

Consider this example:

Accept: application/json, application/xml;q=0.8

@Produces("application/json; application/xml")

The intersection should get "application/json" selected and if it is
done before the response filters run, then
ContainerResponseContext#getMediaType works OK.

Now, if we have no JSON Provider registered (not a mistake), the
consumer should get XML back, so the final response media type should
really be selected depending on the available message body writers,
example, if no JSON provider registered then it actually has to be

"application/xml" - the problem here is that container response filters
and writer interceptors run before MBWs are checked, and thus
ContainerResponseFilter implementations may see the media type which
will not actually be the final response media type.

Does the above make sense, as far as describing the possible issue ?
At the moment I'm thinking to actually pre-check available MBWs in case
of non-null response entities before the filters run, and then re-check
them again if the entity is still not null and the content type gets
changed during the filter/writer interceptor processing.