Custom MessageBodyWriter superseded by build-in MessageBodyWriter

I have a method that produces both "text/plain" and "application/xml". Defined as:

@GET
@Path("/customDtos")
@Produces(

)
public List<CustomDto> getCustomDtos();

CustomDto is a JAXB annotated pojo.

isWriteable always returns true for CollectionProvider, even though it seems it cannot cater for "text/plain". CollectionProvider then fails in writeTo when it tries to find a JAXBContextFinder for "text/plain". Since CollectionProvider's isWriteable returns true my custom MessageBodyWriter is never reached.

Either the CollectionProvider isWriteable should have additional checks if it cannot cater for media type "text/plain" or application MessageBodyWriters should get precedence. Or am I missing something?