Deprecate RxJava 1 in favor of RxJava 2+3 [SPR-15062]

[spring-projects-issues]

Juergen Zimmermann opened SPR-15062 and commented

Dávid Karnok classifies reactive libraries into 0..4 generations at http://akarnokd.blogspot.de/2016/03/operator-fusion-part-1.html. IMHO Project Reactor and RxJava 2 belong to the 4th (and latest) generation while RxJava 1.x belongs to the 2nd generation.
https://github.com/ReactiveX/RxJava/tree/2.x shows the development activites for RxJava 2.

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Affects: 5.0 M3

Reference URL: http://akarnokd.blogspot.de/2016/03/operator-fusion-part-1.html

Issue Links:

• Upgrade to RxJava 1.3 & 2.1 [SPR-15497] #20056 Upgrade to RxJava 1.3 & 2.1
• Upgrade to RxJava 2.2 [SPR-16388] #20934 Upgrade to RxJava 2.2

[spring-projects-issues]

Juergen Hoeller commented

We are generally very Reactor-focused, with RxJava 2 support being a bonus as an immediate alternative. On the other hand, our RxJava 1 support is a purely pragmatic effort: There is a lot of existing RxJava 1 code and expertise out there, including existing datastore drivers etc, so naturally understanding RxJava 1 types seems like a typical Spring thing to do.

Rossen Stoyanchev, what's your end-of-2016 take on this?

[spring-projects-issues]

Rossen Stoyanchev commented

The Netflix OSS stack to my knowledge is still on RxJava 1 and so a project using Spring Cloud with Hystrix today would have to use RxJava 1. RxNetty which we explicitly support in the Spring Framework is also on RxJava 1.

Furthermore I don't even know what it would mean to deprecate RxJava 1 from a Spring Framewok perspecitve. We don't have a hard dependency on RxJava anywhere. The only imports are in the ReactiveAdapterRegistry which is an adaptation abstraction so by definition its purpose is to adapt. The only others are RxNetty related classes which we obviously can't deprecate either.

So really in the end this request makes sense in the RxNetty issue tracker or the Netflix OSS stack, but not much to do here.

[spring-projects-issues]

Juergen Hoeller commented

Alright, I guess we can close this from our perspective then, keeping up RxJava 1 support for the time being.

[spring-projects-issues]

Juergen Hoeller commented

Since RxJava 1.x officially reached EOL now, this one is worth revisiting... maybe not for our 5.1 quite yet but at least for 5.2.

[poutsma]

I feel that the amount of RxJava 1.x code out there has not diminished, regardless of EOL. I vote to keep RxJava 1.x support in for 5.2.

[jhoeller]

With the launch of RxJava 3 next year, it'll be a good time to deprecate RxJava 1.x at least in our Spring Framework 5.3 timeframe.