Topics

Providers ordering


Pavel Bucek
 

Hi Sergey, others,

you suggest that the exception mapper would be part of MVC spec (not the implementation, so not in javax.* package but more like org.impl.something.*?). I think that checking package name is fragile concept and should be avoided if possible, not to mention that this setup would be not ideal for MVC implementations.

I believe we shouldn't introduce new annotations whenever there is a need for a marker (which, in this case, can be easily defined without it); we already do have plenty of them..

Also, note that @Priority is not use to control what is excluded. It is used accordingly to what it is supposed to be used - to sort providers. JAX-RS implementation then needs to pick single one in most occasions and it will naturally pick more important one.

Since I believe we have working proposal (backed up by the implementation), let's stick to following:

- clarify what is built-in and user-defined provider using Santiagos definition:
if it is registered using the JAX-RS API or discovered via class scanning (i.e. annotated with @Provider), then it is user-defined regardless of their physical location (library, container, etc.). Built-in ones should not be made available using those mechanisms.
- define that user-defined providers will be sorted by the @Priority with respect to existing, already defined algorithms. That means it will influence which Provider is defined only when other conditions are already applied and more than one provider is equal in terms of the defined algorithm (i.e. exception type distance for ExceptionMappers).

Described change fits well in Java EE environment, since using @Provider is quite common among other specifications thus is already natural for majority of users.

Please let us know whether you have any strong objections or suggestions how to improve proposed rules.

Thanks and regards,
Pavel


On 25/05/2017 11:30, Sergey Beryozkin wrote:
I guess that what I also suggested when we talked with Christian about @DefaultProvider - the only problem from what I understood MVC will've been already released by the time JAX-RS 2.1 gets out.

To be honest, I'm still thinking, checking the origin (package) of the mapper can work. If for ex MVC ships its ExceptionMapper it is still a built-in mapper in context of MVC, and it can be identified to be a built-in one because it will be in a javax. namespace. Such providers should get a lower priority OOB (compared to the otherwise equal competing mappers), without having to depend on @Priority.

@Priority is there to sort the providers, making sure they execute in the right order. Using it as a mechanism to exclude does not seem quite right...Though it can work...

Cheers, Sergey


Santiago Pericas-Geertsen
 


On May 25, 2017, at 10:40 AM, Sergey Beryozkin <sberyozkin@...> wrote:

Hi Santiago

In what other cases, apart from ensuring a mapper shipped with MVC (or other spec APIs depending on JAX-RS), we would want to support sorting two ExceptionMapper<SomeClass> ?

 That is the main use case AFICT. Any library/framework sitting on top of JAX-RS may need finer control over this. @Priority is already used for filters and interceptors, except that in this case the entire set is consider rather than just one —but there is precedence of using this annotation nonetheless.

 Conceptually, this is what I have in mind, for all providers:

 1. Gather list of candidates
 2. Filter list based on provider-specific predicate
 3. Sort resulting list based on priority
 4. Pick one or all depending on provider kind

— Santiago


Cheers, Sergey
 
On 25/05/17 15:01, Santiago Pericas-Geertsen wrote:

On May 25, 2017, at 2:41 AM, Markus KARG <markus@...> wrote:

I do not see that we cannot change this. If we decide that a new, optional annotation will modify the precedence, this would be perfectly backwards compatible, as all non-annotated code will still work correctly.


 By an annotation you mean something like @PreferBuiltinProviders? I don’t see how that addresses the requirements outlined in JIRA 537.

— Santiago




Sergey Beryozkin
 

Hi Pavel


On 25/05/17 15:54, Pavel Bucek wrote:

Hi Sergey, others,

you suggest that the exception mapper would be part of MVC spec (not the implementation, so not in javax.* package but more like org.impl.something.*?). I think that checking package name is fragile concept and should be avoided if possible, not to mention that this setup would be not ideal for MVC implementations.

I thought that the MVC spec was shipping its own default mapper, that is way I was suggesting checking javax.*.
if it is not the case then I agree it would not work well...

I believe we shouldn't introduce new annotations whenever there is a need for a marker (which, in this case, can be easily defined without it); we already do have plenty of them..

Also, note that @Priority is not use to control what is excluded. It is used accordingly to what it is supposed to be used - to sort providers. JAX-RS implementation then needs to pick single one in most occasions and it will naturally pick more important one.
Leading to the exclusion in the end. With Filters it is obviously not the case, all of them are run.


Since I believe we have working proposal (backed up by the implementation),
IMHO that should not be used to affect the discussion given that the proposal is still under the discussion ?
let's stick to following:

- clarify what is built-in and user-defined provider using Santiagos definition:
if it is registered using the JAX-RS API or discovered via class scanning (i.e. annotated with @Provider), then it is user-defined regardless of their physical location (library, container, etc.). Built-in ones should not be made available using those mechanisms.
- define that user-defined providers will be sorted by the @Priority with respect to existing, already defined algorithms. That means it will influence which Provider is defined only when other conditions are already applied and more than one provider is equal in terms of the defined algorithm (i.e. exception type distance for ExceptionMappers).

Described change fits well in Java EE environment, since using @Provider is quite common among other specifications thus is already natural for majority of users.

Please let us know whether you have any strong objections or suggestions how to improve proposed rules.
Looks like we have no other option but to use @Priority even though it will mean @Priority is used differently when applied to exception mappers (or param converters ?). It feels wrong but I guess we don't have other options (the new annotation will do well but it is just too late for it to be introduced)

Sergey


Thanks and regards,
Pavel


On 25/05/2017 11:30, Sergey Beryozkin wrote:
I guess that what I also suggested when we talked with Christian about @DefaultProvider - the only problem from what I understood MVC will've been already released by the time JAX-RS 2.1 gets out.

To be honest, I'm still thinking, checking the origin (package) of the mapper can work. If for ex MVC ships its ExceptionMapper it is still a built-in mapper in context of MVC, and it can be identified to be a built-in one because it will be in a javax. namespace. Such providers should get a lower priority OOB (compared to the otherwise equal competing mappers), without having to depend on @Priority.

@Priority is there to sort the providers, making sure they execute in the right order. Using it as a mechanism to exclude does not seem quite right...Though it can work...

Cheers, Sergey



Sergey Beryozkin
 

Hi Santiago
On 25/05/17 15:59, Santiago Pericas-Geertsen wrote:

On May 25, 2017, at 10:40 AM, Sergey Beryozkin <sberyozkin@...> wrote:

Hi Santiago

In what other cases, apart from ensuring a mapper shipped with MVC (or other spec APIs depending on JAX-RS), we would want to support sorting two ExceptionMapper<SomeClass> ?

 That is the main use case AFICT. Any library/framework sitting on top of JAX-RS may need finer control over this. @Priority is already used for filters and interceptors, except that in this case the entire set is consider rather than just one —but there is precedence of using this annotation nonetheless.

 Conceptually, this is what I have in mind, for all providers:

 1. Gather list of candidates
 2. Filter list based on provider-specific predicate
 3. Sort resulting list based on priority
 4. Pick one or all depending on provider kind

4. states it well, I agree in the end of the day this is probably the most pragmatic solution

Cheers, Sergey

— Santiago


Cheers, Sergey
 
On 25/05/17 15:01, Santiago Pericas-Geertsen wrote:

On May 25, 2017, at 2:41 AM, Markus KARG <markus@...> wrote:

I do not see that we cannot change this. If we decide that a new, optional annotation will modify the precedence, this would be perfectly backwards compatible, as all non-annotated code will still work correctly.


 By an annotation you mean something like @PreferBuiltinProviders? I don’t see how that addresses the requirements outlined in JIRA 537.

— Santiago





Pavel Bucek
 

Hi Sergey,

please see inline.


On 25/05/2017 17:04, Sergey Beryozkin wrote:
Hi Pavel


On 25/05/17 15:54, Pavel Bucek wrote:

Hi Sergey, others,

you suggest that the exception mapper would be part of MVC spec (not the implementation, so not in javax.* package but more like org.impl.something.*?). I think that checking package name is fragile concept and should be avoided if possible, not to mention that this setup would be not ideal for MVC implementations.

I thought that the MVC spec was shipping its own default mapper, that is way I was suggesting checking javax.*.
if it is not the case then I agree it would not work well...

I believe we shouldn't introduce new annotations whenever there is a need for a marker (which, in this case, can be easily defined without it); we already do have plenty of them..

Also, note that @Priority is not use to control what is excluded. It is used accordingly to what it is supposed to be used - to sort providers. JAX-RS implementation then needs to pick single one in most occasions and it will naturally pick more important one.
Leading to the exclusion in the end. With Filters it is obviously not the case, all of them are run.
yes, exactly.

I was trying to offer another point of view on that issue, seemed like you are suggesting that the proposal uses @Priority in a way that contradicts its purpose.


Since I believe we have working proposal (backed up by the implementation),
IMHO that should not be used to affect the discussion given that the proposal is still under the discussion ?

I'm sorry if that statement felt like something too offensive.

All I wanted to say there was "hey, this proposal does work, we know it, since we do have backing implementation. with tests. :)"

I could use the argument that says "we need to have RI implementation for anything we do propose here, because if we don't, the feature cannot be part of the spec", since we have to have everything ready for PFD, but .. it is not the case here.

let's stick to following:

- clarify what is built-in and user-defined provider using Santiagos definition:
if it is registered using the JAX-RS API or discovered via class scanning (i.e. annotated with @Provider), then it is user-defined regardless of their physical location (library, container, etc.). Built-in ones should not be made available using those mechanisms.
- define that user-defined providers will be sorted by the @Priority with respect to existing, already defined algorithms. That means it will influence which Provider is defined only when other conditions are already applied and more than one provider is equal in terms of the defined algorithm (i.e. exception type distance for ExceptionMappers).

Described change fits well in Java EE environment, since using @Provider is quite common among other specifications thus is already natural for majority of users.

Please let us know whether you have any strong objections or suggestions how to improve proposed rules.
Looks like we have no other option but to use @Priority even though it will mean @Priority is used differently when applied to exception mappers (or param converters ?). It feels wrong but I guess we don't have other options (the new annotation will do well but it is just too late for it to be introduced)

I do see it as "contextual" priority and the context is defined by the provider definition. I don't have any examples from Java EE in mind right now, but sorting something (by the priority) and then picking "the best" provider seems to be natural. Also, if a provider is a filter and filter contract defines that all filters have to be executed, then using @Priority for sorting them doesn't feel wrong. I do agree that there is a difference, but the difference is in providers declaration, not in the semantics of @Priority.

Of course, I can be wrong ;) Please let me know what do you think.

Best regards,
Pavel


Sergey


Thanks and regards,
Pavel


On 25/05/2017 11:30, Sergey Beryozkin wrote:
I guess that what I also suggested when we talked with Christian about @DefaultProvider - the only problem from what I understood MVC will've been already released by the time JAX-RS 2.1 gets out.

To be honest, I'm still thinking, checking the origin (package) of the mapper can work. If for ex MVC ships its ExceptionMapper it is still a built-in mapper in context of MVC, and it can be identified to be a built-in one because it will be in a javax. namespace. Such providers should get a lower priority OOB (compared to the otherwise equal competing mappers), without having to depend on @Priority.

@Priority is there to sort the providers, making sure they execute in the right order. Using it as a mechanism to exclude does not seem quite right...Though it can work...

Cheers, Sergey




Sergey Beryozkin
 

Hi Pavel

Thanks, sorry, your note re having a working implementation was not of the most major concern :-), I was only trying to imply that
well, sometimes we have to be ready to adjust our code, though I know RI has a good code :-).
Either way, as far as I'm concerned, I reckon we can probably won't have a better alternative to using @Priority

Thanks, Sergey

On 25/05/17 16:19, Pavel Bucek wrote:

Hi Sergey,

please see inline.


On 25/05/2017 17:04, Sergey Beryozkin wrote:
Hi Pavel


On 25/05/17 15:54, Pavel Bucek wrote:

Hi Sergey, others,

you suggest that the exception mapper would be part of MVC spec (not the implementation, so not in javax.* package but more like org.impl.something.*?). I think that checking package name is fragile concept and should be avoided if possible, not to mention that this setup would be not ideal for MVC implementations.

I thought that the MVC spec was shipping its own default mapper, that is way I was suggesting checking javax.*.
if it is not the case then I agree it would not work well...

I believe we shouldn't introduce new annotations whenever there is a need for a marker (which, in this case, can be easily defined without it); we already do have plenty of them..

Also, note that @Priority is not use to control what is excluded. It is used accordingly to what it is supposed to be used - to sort providers. JAX-RS implementation then needs to pick single one in most occasions and it will naturally pick more important one.
Leading to the exclusion in the end. With Filters it is obviously not the case, all of them are run.
yes, exactly.

I was trying to offer another point of view on that issue, seemed like you are suggesting that the proposal uses @Priority in a way that contradicts its purpose.


Since I believe we have working proposal (backed up by the implementation),
IMHO that should not be used to affect the discussion given that the proposal is still under the discussion ?

I'm sorry if that statement felt like something too offensive.

All I wanted to say there was "hey, this proposal does work, we know it, since we do have backing implementation. with tests. :)"

I could use the argument that says "we need to have RI implementation for anything we do propose here, because if we don't, the feature cannot be part of the spec", since we have to have everything ready for PFD, but .. it is not the case here.

let's stick to following:

- clarify what is built-in and user-defined provider using Santiagos definition:
if it is registered using the JAX-RS API or discovered via class scanning (i.e. annotated with @Provider), then it is user-defined regardless of their physical location (library, container, etc.). Built-in ones should not be made available using those mechanisms.
- define that user-defined providers will be sorted by the @Priority with respect to existing, already defined algorithms. That means it will influence which Provider is defined only when other conditions are already applied and more than one provider is equal in terms of the defined algorithm (i.e. exception type distance for ExceptionMappers).

Described change fits well in Java EE environment, since using @Provider is quite common among other specifications thus is already natural for majority of users.

Please let us know whether you have any strong objections or suggestions how to improve proposed rules.
Looks like we have no other option but to use @Priority even though it will mean @Priority is used differently when applied to exception mappers (or param converters ?). It feels wrong but I guess we don't have other options (the new annotation will do well but it is just too late for it to be introduced)

I do see it as "contextual" priority and the context is defined by the provider definition. I don't have any examples from Java EE in mind right now, but sorting something (by the priority) and then picking "the best" provider seems to be natural. Also, if a provider is a filter and filter contract defines that all filters have to be executed, then using @Priority for sorting them doesn't feel wrong. I do agree that there is a difference, but the difference is in providers declaration, not in the semantics of @Priority.

Of course, I can be wrong ;) Please let me know what do you think.

Best regards,
Pavel


Sergey


Thanks and regards,
Pavel


On 25/05/2017 11:30, Sergey Beryozkin wrote:
I guess that what I also suggested when we talked with Christian about @DefaultProvider - the only problem from what I understood MVC will've been already released by the time JAX-RS 2.1 gets out.

To be honest, I'm still thinking, checking the origin (package) of the mapper can work. If for ex MVC ships its ExceptionMapper it is still a built-in mapper in context of MVC, and it can be identified to be a built-in one because it will be in a javax. namespace. Such providers should get a lower priority OOB (compared to the otherwise equal competing mappers), without having to depend on @Priority.

@Priority is there to sort the providers, making sure they execute in the right order. Using it as a mechanism to exclude does not seem quite right...Though it can work...

Cheers, Sergey





 

By annotation I mean something like "@UseThisProviderOnlyIfNonIsBuiltIn" attached to an application-provided provider (certainly with a smarter name).

 

It is unrelated to any JIRA issue. I just came into my mind as we had this requirement several times in the past, which always ended up the same: The application provided a fallback provider (just to be sure there will be one), so the potential built-in one always was skipped -- rendering the built-in useless.

 

This annotation is needed whenever an application wants to trust a particular feature to be provided, but the JAX-RS specification does not mandate this feature. Thinks of support for OAuth for example, which is optional currently, but may be mandatory in future. Applications could provide own OAuth now and markt it as "fall-back-only". Or JSON-B. etc.

 

-Markus

 

From: jaxrs-spec@javaee.groups.io [mailto:jaxrs-spec@javaee.groups.io] On Behalf Of Santiago Pericas-Geertsen
Sent: Donnerstag, 25. Mai 2017 16:02
To: jaxrs-spec@javaee.groups.io
Subject: Re: [jaxrs] Providers ordering

 

 

On May 25, 2017, at 2:41 AM, Markus KARG <markus@...> wrote:

 

I do not see that we cannot change this. If we decide that a new, optional annotation will modify the precedence, this would be perfectly backwards compatible, as all non-annotated code will still work correctly.

 

 By an annotation you mean something like @PreferBuiltinProviders? I don’t see how that addresses the requirements outlined in JIRA 537.

 

— Santiago

 


Pavel Bucek
 

FYI:

Custom providers without @Provider annotation will have priority value javax.ws.rs.Priorities.USER (value 5000).

Also, Priority(100) > Prority(500), so provider with Priority(100) will be processed before provider with Priority(500).

More details can be found in the updated spec document, see change https://github.com/jax-rs/spec/commit/817c16fdf8cd8528041b7597bc19f4f7e010ec88 .

Regards,
Pavel


On 25/05/2017 16:54, Pavel Bucek wrote:

Hi Sergey, others,

you suggest that the exception mapper would be part of MVC spec (not the implementation, so not in javax.* package but more like org.impl.something.*?). I think that checking package name is fragile concept and should be avoided if possible, not to mention that this setup would be not ideal for MVC implementations.

I believe we shouldn't introduce new annotations whenever there is a need for a marker (which, in this case, can be easily defined without it); we already do have plenty of them..

Also, note that @Priority is not use to control what is excluded. It is used accordingly to what it is supposed to be used - to sort providers. JAX-RS implementation then needs to pick single one in most occasions and it will naturally pick more important one.

Since I believe we have working proposal (backed up by the implementation), let's stick to following:

- clarify what is built-in and user-defined provider using Santiagos definition:
if it is registered using the JAX-RS API or discovered via class scanning (i.e. annotated with @Provider), then it is user-defined regardless of their physical location (library, container, etc.). Built-in ones should not be made available using those mechanisms.
- define that user-defined providers will be sorted by the @Priority with respect to existing, already defined algorithms. That means it will influence which Provider is defined only when other conditions are already applied and more than one provider is equal in terms of the defined algorithm (i.e. exception type distance for ExceptionMappers).

Described change fits well in Java EE environment, since using @Provider is quite common among other specifications thus is already natural for majority of users.

Please let us know whether you have any strong objections or suggestions how to improve proposed rules.

Thanks and regards,
Pavel


On 25/05/2017 11:30, Sergey Beryozkin wrote:
I guess that what I also suggested when we talked with Christian about @DefaultProvider - the only problem from what I understood MVC will've been already released by the time JAX-RS 2.1 gets out.

To be honest, I'm still thinking, checking the origin (package) of the mapper can work. If for ex MVC ships its ExceptionMapper it is still a built-in mapper in context of MVC, and it can be identified to be a built-in one because it will be in a javax. namespace. Such providers should get a lower priority OOB (compared to the otherwise equal competing mappers), without having to depend on @Priority.

@Priority is there to sort the providers, making sure they execute in the right order. Using it as a mechanism to exclude does not seem quite right...Though it can work...

Cheers, Sergey



 

Hi Pavel,

thanks a lot the explanation. I just had a look at the changes and it looks good.

One minor thing. One of the new paragraphs state:

  All application-supplied providers implement interfaces in the JAX-RS API and MAY be annotated with @Priority for automatic discovery purposes

I guess this should be @Provider, correct?



Christian


2017-05-29 10:31 GMT+02:00 Pavel Bucek <pavel.bucek@...>:

FYI:

Custom providers without @Provider annotation will have priority value javax.ws.rs.Priorities.USER (value 5000).

Also, Priority(100) > Prority(500), so provider with Priority(100) will be processed before provider with Priority(500).

More details can be found in the updated spec document, see change https://github.com/jax-rs/spec/commit/817c16fdf8cd8528041b7597bc19f4f7e010ec88 .

Regards,
Pavel


On 25/05/2017 16:54, Pavel Bucek wrote:

Hi Sergey, others,

you suggest that the exception mapper would be part of MVC spec (not the implementation, so not in javax.* package but more like org.impl.something.*?). I think that checking package name is fragile concept and should be avoided if possible, not to mention that this setup would be not ideal for MVC implementations.

I believe we shouldn't introduce new annotations whenever there is a need for a marker (which, in this case, can be easily defined without it); we already do have plenty of them..

Also, note that @Priority is not use to control what is excluded. It is used accordingly to what it is supposed to be used - to sort providers. JAX-RS implementation then needs to pick single one in most occasions and it will naturally pick more important one.

Since I believe we have working proposal (backed up by the implementation), let's stick to following:

- clarify what is built-in and user-defined provider using Santiagos definition:
if it is registered using the JAX-RS API or discovered via class scanning (i.e. annotated with @Provider), then it is user-defined regardless of their physical location (library, container, etc.). Built-in ones should not be made available using those mechanisms.
- define that user-defined providers will be sorted by the @Priority with respect to existing, already defined algorithms. That means it will influence which Provider is defined only when other conditions are already applied and more than one provider is equal in terms of the defined algorithm (i.e. exception type distance for ExceptionMappers).

Described change fits well in Java EE environment, since using @Provider is quite common among other specifications thus is already natural for majority of users.

Please let us know whether you have any strong objections or suggestions how to improve proposed rules.

Thanks and regards,
Pavel


On 25/05/2017 11:30, Sergey Beryozkin wrote:
I guess that what I also suggested when we talked with Christian about @DefaultProvider - the only problem from what I understood MVC will've been already released by the time JAX-RS 2.1 gets out.

To be honest, I'm still thinking, checking the origin (package) of the mapper can work. If for ex MVC ships its ExceptionMapper it is still a built-in mapper in context of MVC, and it can be identified to be a built-in one because it will be in a javax. namespace. Such providers should get a lower priority OOB (compared to the otherwise equal competing mappers), without having to depend on @Priority.

@Priority is there to sort the providers, making sure they execute in the right order. Using it as a mechanism to exclude does not seem quite right...Though it can work...

Cheers, Sergey






Pavel Bucek
 

Hi Christian.

Yes, you are right, that's a "typo".

Thanks for letting us know :)

Regards,
Pavel

On 29/05/2017 10:43, Christian Kaltepoth wrote:
Hi Pavel,

thanks a lot the explanation. I just had a look at the changes and it looks good.

One minor thing. One of the new paragraphs state:

  All application-supplied providers implement interfaces in the JAX-RS API and MAY be annotated with @Priority for automatic discovery purposes

I guess this should be @Provider, correct?



Christian


2017-05-29 10:31 GMT+02:00 Pavel Bucek <pavel.bucek@...>:

FYI:

Custom providers without @Provider annotation will have priority value javax.ws.rs.Priorities.USER (value 5000).

Also, Priority(100) > Prority(500), so provider with Priority(100) will be processed before provider with Priority(500).

More details can be found in the updated spec document, see change https://github.com/jax-rs/spec/commit/817c16fdf8cd8528041b7597bc19f4f7e010ec88 .

Regards,
Pavel


On 25/05/2017 16:54, Pavel Bucek wrote:

Hi Sergey, others,

you suggest that the exception mapper would be part of MVC spec (not the implementation, so not in javax.* package but more like org.impl.something.*?). I think that checking package name is fragile concept and should be avoided if possible, not to mention that this setup would be not ideal for MVC implementations.

I believe we shouldn't introduce new annotations whenever there is a need for a marker (which, in this case, can be easily defined without it); we already do have plenty of them..

Also, note that @Priority is not use to control what is excluded. It is used accordingly to what it is supposed to be used - to sort providers. JAX-RS implementation then needs to pick single one in most occasions and it will naturally pick more important one.

Since I believe we have working proposal (backed up by the implementation), let's stick to following:

- clarify what is built-in and user-defined provider using Santiagos definition:
if it is registered using the JAX-RS API or discovered via class scanning (i.e. annotated with @Provider), then it is user-defined regardless of their physical location (library, container, etc.). Built-in ones should not be made available using those mechanisms.
- define that user-defined providers will be sorted by the @Priority with respect to existing, already defined algorithms. That means it will influence which Provider is defined only when other conditions are already applied and more than one provider is equal in terms of the defined algorithm (i.e. exception type distance for ExceptionMappers).

Described change fits well in Java EE environment, since using @Provider is quite common among other specifications thus is already natural for majority of users.

Please let us know whether you have any strong objections or suggestions how to improve proposed rules.

Thanks and regards,
Pavel


On 25/05/2017 11:30, Sergey Beryozkin wrote:
I guess that what I also suggested when we talked with Christian about @DefaultProvider - the only problem from what I understood MVC will've been already released by the time JAX-RS 2.1 gets out.

To be honest, I'm still thinking, checking the origin (package) of the mapper can work. If for ex MVC ships its ExceptionMapper it is still a built-in mapper in context of MVC, and it can be identified to be a built-in one because it will be in a javax. namespace. Such providers should get a lower priority OOB (compared to the otherwise equal competing mappers), without having to depend on @Priority.

@Priority is there to sort the providers, making sure they execute in the right order. Using it as a mechanism to exclude does not seem quite right...Though it can work...

Cheers, Sergey





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