[jax-rs-spec users] Re: JAX-RS 2.1 - work schedule

From: Sergey Beryozkin <>
Date: Sat, 14 Jan 2017 10:30:49 +0000

I'm def not going to continue trying to convince you, we both know we can talk long threads which can lead to nowhere :-),
I'm supporting the current proposal and honestly hope most experts will support it too, though of course I'm open to the improvements, as long as the possibility to plug in non-default reactive implementations remains

On 13/01/17 22:19, Markus KARG wrote:

I completely understand the importance _current_ Spring importance, but you still do not get what I mean. It is totall OK to provide _extensibility_ so people can use Spring or whatever. My sole critics is about the _way_ the current proposal tries to support that. It makes the API too complex if inside a code block you have to repeat the decision "I want spring, not CompletableStage" again and again. I would love to see an _S_PI (not _A_PI!) that allows one to _statically replace_ the RX provider used by JAX-RS instead of asking for a particular return type for each single rx() invocation. What bothers me is particularly the existence of the methods rx() and rx(Class) as I am convinced that it is better to e. g. have RxClient (that statically is reactive inherently) and and .unwrap() method that one can optionally attach _if needed_. I do not want to repeat rx() egain and again, and I do not want to repeat the return type again and again. That's all.

Besides that, my option is that all reactive frameworks will die once Java 10 has "real" reactive API on board. But whether this is the case or not is irrelevant for the further discussion of the API itself. We should concentrate on finding a concensus how the API shall look like, not on repeating our arguments and try to convince us about this or that vision of the future.


From: Sergey Beryozkin []
Sent: Freitag, 13. Januar 2017 21:02
Subject: Re: [jax-rs-spec users] JAX-RS 2.1 - work schedule

sorry, I'm a bit tired (and sick) today, so may be I've missed something, but no, I do not support your arguments.
Having a good standard is good, agreed. And having a standard which is clever enough to let people work with a standard
API, while in this case, being able optionally to support RxJava or something else that will come tomorrow, is a massive plus.

I know firsthand, 100%, that JAX-RS is losing to Spring WS/RS in some cases. It is not only about creating a standard for the sake of creating a standard
but is about creating a standard which will stay alive and competitive.

I do encourage you to actually have a look at the proposed RxInvoker and check the examples, there was also a good Jersey blog awhile back on their prototype of working with RxJava which I reckon led to RxInvoker idea...


On 13/01/17 19:02, Markus KARG wrote:
I understand your arguments and I hope you understand mine too. As I am a member of the JCP solely for the sake of creating industrial standars (hence not of creating products), I have a slightly differen view of this. I think it is critical that JAX-RS stays focused on long-term evolution instead of extensibity of the current evolutionary step.

The question now is, somebody has to decide what the final API shall be like: (even slightly) more complex for each code line where it is getting used but for the sake of being extendable - vs. - concise (and slightly higher performant) - vs. - both variants. My vote is that we only support CompletableStage in JAX-RS 2.1, and come up with additional Java-10-native-RX-API support in JAX-RS 3.0 or 3.1, but not to keep the API pluggable for any product that is not standardized by the JCP while ALL (!) OTHER APIs of Java EE do not care the least about those products (independent of their popularity).

A second issue I can remember is that I asked whether it makes sense to directly request a reactive client once (i. e. all further calls bear CompletableStage), or whether we really want users to request a reactive invocation for each and every invocation. I cannot remember that _that_ discussion ended with any concensus.

But the question is, whether the Spec Lead decides that alone without further discussion of the EG members, or whether the EG members have a real say in that as in a democratic project. This is something Santiago has to tell us. See, I don't want to bother, I actually just want to have clear rules to follow. The JCP says, the EG defines the outcome. So we should at least shortly discuss the pros and cons of different API variants as other JSRs do, too, and not just nod through one single proposal for the sole sake of getting done earlier.


From: Sergey Beryozkin [<>]
Sent: Donnerstag, 12. Januar 2017 21:04
Subject: Re: [jax-rs-spec users] JAX-RS 2.1 - work schedule

Have a look please at the proposed API, rx() is simply a bridge into a CompletableStage, while another rx(...) overload (which I have some separate techincail issues with) will let users plug-in other reactive implementations, while still working with JAX-RS 2.1 API - only a type variable will differ. IMHO it is critical JAX-RS stays more open (rx() and rx(...) is a good example)


On 12/01/17 19:06, Sergey Beryozkin wrote:
Standards, standards. You keep forgetting that today many users do not care about standards but about being able to use the good, proven to work technologies in their work.
We should learn from Spring WS/REST.

> In the end, what we decide, is frozen for decades. I mean, that's a difference between breeding an international standard and simply providing a good API _for now_.
The standard which noone will use ? rx() will not force people to use what you do not consider a proper standard
On 12/01/17 18:53, Markus KARG wrote:
RxJava is not a JCP standard, and popularity can change easily. So it is doubtful whether non-standards have to be taken core of by standards. I cannot see any other JCP standard that enforces a detour in the API just for the sake of supporting non-standards. Correct me if I am wrong. A better way would be defining an SPI, or configuration, too statically choose in the bootstrat. I doubt that applications will mix differen RX implementations at runtime, so there is no need to say "I want RxJava" with every single call of the API.

Yes, Java 10. I heared that it might provide an official RX standard for Java SE. So JAX-RS "3+" might be facing a situation whethere it has to support an official standard. We have to take care that decisions for JAX-RS today must not stand in the way of usefulness and conciseness of JAX-RS in the future. I hardly think that in two or three years people like the idea that they have to write "rx(Classname)" always if possibly Java 10's reactive API took over and nobody talks about CompletableStage and RxJava anymore.

In the end, what we decide, is frozen for decades. I mean, that's a difference between breeding an international standard and simply providing a good API _for now_.


From: Sergey Beryozkin [<>]
Sent: Donnerstag, 12. Januar 2017 18:56
Subject: Re: [jax-rs-spec users] JAX-RS 2.1 - work schedule

Java 10 ? JAX-RS 2.1 is Java 8 based, and RxJava is highly popular so voluntarily restricting 2.1. to CompletableStage only would be a mistake...
On 12/01/17 17:10, Markus KARG wrote:
The question is whether we actually want the ability to support other reactive implementations, or whether we decide to stick with CompletableStage? The rx intermediate method makes the API more complex for anybody. On the other hand, Java 10 possibly will provide a "real" reactive API for everyone, and we cannot natively support it, but enforce people to use rx() still, which is tedious. I cannot remember that the EG actually agreed upon a final answer of this dilemma.

From: Santiago Pericasgeertsen [<>]
Sent: Donnerstag, 12. Januar 2017 16:00
Subject: Re: [jax-rs-spec users] JAX-RS 2.1 - work schedule

On Jan 11, 2017, at 4:17 PM, Pavel Bucek <<>> wrote:

So what's going to happen next? We are currently working in PoC implementation of Reactive client API which is currently in the JAX-RS source repository master branch - it is almost ready for review. We identified small improvement needed there and I'm going to take care of that, finish the PoC implementation and document the API on the wiki. Once this is done, I'll send a request for review to this mailing list.

 Just a quick reminder that the crux of the RX work is the addition of new rx() methods to Invocation, with default support for CompletionStage and an extension point to plug in other reactive implementations via the RxInvoker type [1].

- Santiago