Out-of-the-box build compatibility with JDK 9 build 136 [SPR-14645]

[spring-projects-issues]

Juergen Hoeller opened SPR-14645 and commented

The Spring Framework 5.0 M1 build ran on JDK 9 already but required a manual Gradle upgrade. As of 5.0 M2, we're building on Gradle 3.0 out of the box, so our entire framework build can run on JDK 9 out of the box as well. Let's verify our compatibility against the latest JDK 9 snapshot.

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Affects: 5.0 M1

Issue Links:

• Compatibility with merged JDK 9 mainline [SPR-13344] #17928 Compatibility with merged JDK 9 mainline ("depends on")
• Upgrade build to Gradle 3.0 [SPR-14569] #19138 Upgrade build to Gradle 3.0 ("depends on")
• Compatibility with JDK 9 release candidate [SPR-15686] #20245 Compatibility with JDK 9 release candidate

[spring-projects-issues]

Juergen Hoeller commented

Our JDK 9 CI build revealed a breakage in AnnotationUtilsTests.toStringForSynthesizedAnnotations where we relied on a particular Annotation.toString representation from the JDK. However, since no particular format is guaranteed there, I've reduced those checks to our own synthesized annotations.

[spring-projects-issues]

Sam Brannen commented

Hmmmm... that's rather shocking that the toString() implementation for annotations has changed on JDK 9.

I'd be interested to see what the new format is.

In any case, thanks for making the test more robust.

[spring-projects-issues]

Juergen Hoeller commented

See https://build.spring.io/browse/SPR-JDK9-JOB1-8/test/case/208995888

They seem to have changed the bracket style, also exposing additional quotes now.

[spring-projects-issues]

Sam Brannen commented

Aha.

So, basically, the new format aligns with the actual syntax from the Java source code.

Interesting!

[spring-projects-issues]

Juergen Hoeller commented

Netty's NioEventLoopGroup doesn't work on current JDK 9 builds out of the box since it depends on sun.nio.ch.SelectorImpl which the java.base module doesn't export by default anymore. With some conditional extra exports added to Gradle's test JVMs, all of our tests pass again.