[jmx-scraper] keep old servlet API and java8 compatibility

[SylvainJuge]

• Pin servlet version to 5.0.0 to prevent update PRs like fix(deps): update dependency jakarta.servlet:jakarta.servlet-api to v6 - autoclosed #1543
• use java source and target code level instead of toolchain contraints, given there isn't any java 8 compatible toolchain available for aarch64, we can replace it with any other compatible version that can compile to Java 8 (and let gradle find a suitable one).

[trask]

I've opened #1554 with the needed changes to the renovate config bundled with another change that allows building on recent ARM-based MacOS systems.

can you explain this part a bit more? why is it only a problem for these two modules? thanks!

[SylvainJuge]

can you explain this part a bit more? why is it only a problem for these two modules? thanks!

Yes this is only for those two modules.

The problem here was that instead of just "compiling to java 8" we used to require to have a Java 8 SDK (aka "toolchain" for gradle) installed to compile the module.

For example with Temurin: https://adoptium.net/temurin/releases/?os=mac&arch=aarch64&version=8 returns nothing, but we should be able to use JDK 11 or any later JDK version that allows to compile to java 8. From what I understand this is problematic only on ARM-based Macs because there is no aarch64 variant for JDK 8, so gradle can't find nor even try to download it when needed.

[trask]

can you check if this addresses the issue? #1555

[SylvainJuge]

#1555 fixes the issue, so I'll close this PR. Thanks @robsunday for double-checking it now works as expected in MacOS + ARM.

[laurit]

From what I understand this is problematic only on ARM-based Macs because there is no aarch64 variant for JDK 8, so gradle can't find nor even try to download it when needed.

FYI corretto has aarch64 jdk8 for mac.