[jax-rs-spec users] Re: Proposal to drop non-blocking I/O from JAX-RS 2.1

From: Sergey Beryozkin <>
Date: Tue, 4 Apr 2017 14:49:37 +0100

Hi Pavel

It's disappointing even though I appreciate the effort done so far.
Probably the most important feature we could've done and now we will
face +N (or more) years of waiting for JAX-RS be NIO ready, and by the
time it will happen everyone will already be using Spring RS anyway who
are charging ahead as we speak with top-class Reactive support...
I don't know, we will have though SSE which not all browser implement,
I'd rather have only NIO instead of SSE.
The 'Flow' duplication argument is not convincing because I believe you
had a plan after all to get rid of it when we get to Java 9.
The mid of April constraints just highlights that the process once again
defeats us completing the work which was planned

Thanks, Sergey

On 03/04/17 17:40, Pavel Bucek wrote:
> Dear EG members,
> As you all know we have been hard at work trying to come up with an
> NIO proposal based on Flows. In doing so, we have come to the
> conclusion that this is indeed a really hard problem --lots of small
> details that need double clicking! After some deliberation, we have
> come to the conclusion that it is better to drop this feature from
> this dot release. Here is the rationale for doing so:
> - Working backwards from the officially committed Java EE 8 release
> date - July 2017 - we need to start Public Review in the middle of
> April, which means that at this point we don't have enough time to do
> a design, implementation prototype and gather appropriate feedback.
> - Current proposal is based on a Flow-like API, which would force us
> to duplicate the JDK 9 Flow concept in the JAX-RS 2.1 API.
> - We don't want to introduce "just another non-blocking API", which
> might be deprecated very soon (when Java 9 is released).
> - We need some time to work on "smaller issues", which would be most
> likely not possible if we'll continue working on NIO.
> *What does that mean for the current state of the API?*
> We will remove Flow.* interfaces and its usage in existing APIs, which
> means adjustments in SSE part of the spec. Also, we will be making at
> least some improvement, more related to already introduced Reactive
> API - support for returning CompletionStage from the resource method.
> It was in our last version of the high level non-blocking API;
> CompletionStage is basically a Mono - publisher of a single item.
> Resource method could then look like:
> @POST @Path("acceptProduceSource")
> public CompletionStage<AnotherPOJO> echoNioEntity(POJO requestEntity) {
> // not blocking the thread, returning CompletionStage and doing the
> work elsewhere. return ...;
> }
> This improvement will simplify use of the new JAX-RS 2.1 reactive
> client API in a JAX-RS resource method. Note that this is already
> tracked as
> As always, any comments or suggestions are appreciated.
> Thanks and regards,
> Pavel & Santiago