[jax-rs-spec users] [jsr339-experts] Re: Re: ExceptionMappers and WebApplicationExceptions

From: Sergey Beryozkin <>
Date: Tue, 30 Oct 2012 10:41:30 +0000

On 25/10/12 22:23, Sergey Beryozkin wrote:
> On 25/10/12 22:16, Marek Potociar wrote:
>> FWIW, what I recall we did agree upon, which is however not yet in the
>> spec is that we will make sure that all internal server-side WAEs will
>> be changed to proper sub-types.
> Can you clarify that a bit please ? What would be a difference between
> the internal code throwing WebApplicationException(500) and application
> code doing the same, as far as mapping either of these instances to a
> registered InternalServerErrorException mapper ?

I'd like to get the agreement on this please. What makes me feel that
mapping of WebApplicationException to more specific exception mappers on
the server side should work is because say

WebApplicationException(500) and InternalServerErrorException are meant
to represent exactly the same error condition, so, even though having
the current WebApplicationException handled by
InternalServerErrorException mapper does not work with the current
exception mapping algorithm, the exception has to be made specifically
for WebApplicationException hierarchy - it would just avoid the
ambiguities, example,

"I want to have a generic exception mapping code, implemented with
WebApplicationException mapper, and something more specific done in case
of 500, implemented with InternalServerErrorException mapper".

I know it all can be easily done at the WebApplicationException mapper
level itself, but the introduction of the new exception hierarchy will
inevitably lead to users wishing to write a cleaner base code for
handling all the exceptions without "ifs"


>> Similarly, we agreed that on client side, proper sub-type will be
>> thrown based on response error code instead of a generic WAE.
> That definitely makes sense
>> As for your question, I'm not sure it is wise to interfere with
>> application-thrown exceptions. (And I still cannot recall what we
>> decided...)
> The question is whether some specific treatment is applied to WAE
> instances (irrespectively of where they originated from) or not, I've no
> strong opinion, in fact I've already implemented what I thought we
> might've agreed :-), but that is not important, I can revert, we just
> need to agree
> Sergey
>> Marek
>> On Oct 25, 2012, at 11:10 PM, Marek
>> Potociar<> wrote:
>>> On Oct 25, 2012, at 10:57 PM, Sergey Beryozkin<>
>>> wrote:
>>>> Hi
>>>> I would like to clarify the details of the way
>>>> WebApplicationExceptions are mapped on the server.
>>>> Here is what I recall we talked about the other day.
>>>> The code throws "new WebApplicationException(404)", and both
>>>> WebApplicationException and NotFoundException mappers are available.
>>>> Given NotFoundException is effectively WebApplicationException(404),
>>>> NotFoundException mapper is chosen.
>>> Hmm... are you referring to a specific section in the spec? I cannot
>>> recall we agreed on that one, but I may be wrong.
>>>> Similarly, if the code throws "new ServerErrorException(500)" and both
>>>> ServerErrorException and InternalServerErrorException mappers are
>>>> available, InternalServerErrorException gets chosen.
>>>> Is it the way it should work ? This obviously is an exception to the
>>>> default mapping algorithm, but it appears it is logical given that
>>>> the runtime understands the relationship between various API
>>>> exception classes
>>> As I said, I don't recall such agreement, but my memory is not
>>> flawless... If you see it in the spec, then we did agree on that :)
>>> (Which still doesn't mean we didn't if you don't see it there...)
>>> Marek
>>>> Cheers. Sergey