Adding JDK 11 to CI and docs

[martin-gaievski]

Description

Adding JDK 11 to CI matrix of java versions, replacing as minimum prerequisite in Dev readme guide. Main reason for change - JDK 11 is the latest supported LTS. For now I couldn't make JDK 8 and 17 work, plugin build has multiple issues with each of those versions.

Issues Resolved

#220

Check List

• New functionality has been documented.
  • New functionality has section in md file(s)
• Commits are signed as per the DCO using --signoff

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[jmazanec15]

Thanks @martin-gaievski. For 8 and 17, would you be able to post the relevant stack traces in the issue?

[martin-gaievski]

Thanks @martin-gaievski. For 8 and 17, would you be able to post the relevant stack traces in the issue?

Sure, for JDK 8 it's OS, seems it has been compiled with JDK 9:

org/opensearch/gradle/plugin/PluginPropertiesExtension has been compiled by a more recent version of the Java Runtime (class file version 54.0), this version of the Java Runtime only recognizes class file versions up to 52.0

https://github.com/martin-gaievski/k-NN/runs/4945583353?check_suite_focus=true

for JDK 17 higher gradle version is required, I've tested with 7.3.3. It fails with

Error: Exception in thread "main" java.lang.NoClassDefFoundError: org/gradle/cli/CommandLineParser
	at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:43)

https://github.com/opensearch-project/k-NN/runs/4957612326?check_suite_focus=true
I've tried multiple things locally - different gradle versions, generating new gradle wrapper, setting java language level for tooling etc., but no success.

I've dropped email to Daniel, haven't got an answer yet.

[jmazanec15]

Thanks @martin-gaievski

Please paste those in #220 so we can continue discussion there.

[martin-gaievski]

Thanks @martin-gaievski

Please paste those in #220 so we can continue discussion there.

sure, added same comment to the issue