Nearly there

Spring 5 RC 3 announced: Springing towards a September GA release

Jane Elizabeth
Spring 5
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Spring 5 is already feature-complete, but its extended release candidate phase allows for a more solid GA release of Spring Framework 5.0 in September. Let’s take a look and see what’s already done for the final version and what still needs a little bit of TLC.

Juergen Hoeller, the co-founder and project lead of the Spring Framework open source project, has just announced the release of Spring Framework 5.0 RC3. Spring 5 is already feature-complete and has been since May. However, the extended release phase has allowed the Spring team to dot their i’s and cross their t’s. Also, it gives them time to update a bunch of APIs.

Hoeller points out specifically that Spring 5 should be available in September, matching the new general availability target for Java 9. (Hopefully.)

What’s new?

This release candidate is the third and final milestone in Spring’s roadmap to Spring 5. So, what do we have?

  • Refined nullability and declarations, including the field and bean property level
  • Stronger Kotlin support with a declarative bean definition DSL
  • Support for default constructor arguments on Kotlin data classes
  • Several API refinements in Spring WebFlux
  • Spring Framework 5.0 RC3 ships against Reactor 3.1 M3 and JUnit 5.0 M6
  • Fully tested against the recent Java 9 release candidate.

That seems like a lot of updates and upgrades. So what’s left to do? According to Hoeller, a proper upgrade to Reactor 3.1 GA, JUnit 5.0 GA, and Jackson 2.9 GA are all expected to be finished in time for a September release. Also, further hardening of our revised APIs. So, they do still have some work left over at Spring.

Oh, but what about Spring Boot?

We spoke to Stéphane Nicoll earlier this year about how Spring 5 will affect fan favorite Spring Boot.

“Spring Framework 5 introduces a comprehensive support for reactive programming as an alternative to the traditional blocking model based on the Servlet API,” said Nicoll. “Spring Boot 2 obviously integrates those changes with a new “webflux” starter based on Netty that gives you the same getting started experience than the one you know with the web starter.”

SEE MORE: Feature-complete Spring Framework 5.0 RC1 is here

“Spring 5 also embraces functional programming and provides several building blocks that allow you to compose your applications,” Nicholl pointed out. “If you decide to define your router that way (rather than using annotations) we [Spring Boot] will detect that and configure the server accordingly.”

So, should Spring Boot fans be worried? Not really.

Nicholl went on to point out that Kotlin is a first-class language for Spring Boot and thus supported quite naturally. Users will be allowed to be “functional all the way”. “Spring Boot 2 will also provide dedicated extensions for Kotlin so that you can use all the power of the language.”

Read the rest of the interview here.



Jane Elizabeth
Jane Elizabeth is an assistant editor for

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