Tracking: V2 setup-java

This issue will track the progress of the v2 version of setup-java.

One of the core goals of the v2 version is to support downloading different distributions of Java. Currently Zulu builds of OpenJDK are downloaded and installed but with v2 we will be adding support for adoptOpenJDK builds of OpenJDK as well. Because this is a major change, a v2 major update is warranted.

One of the main goals of v2 is also to make setup-java extensible so that other distributions can be supported as well.

Major TODO items:

• Create ADR that outlines and documents the roadmap and plan for the v2 version: https://github.com/actions/setup-java/pull/97
• Accept ADR after getting feedback from the community
• Create v2-preview branch
• Implement all the necessary changes and merge them into the v2-preview branch
• Gather feedback and test using the v2-preview branch
• After being comfortable with the v2-preview changes, merge the branch into main
• Update public docs, and starter workflow to use v2 instead of v1 tags

[giltene]

I would suggest changing the stated goal (in the PR and ADR) to adding support for multiple distos (rather than a specific one). I believe that is the actual subject for which there is wide demand and support.

I would also propose that we add a goal to address https://github.com/actions/setup-java/issues/84 (built in use of caching) in v2, as this will likely significantly improve workflow execution times and reduce bandwidth requirements.

Another (seemingly minor, but affects expected output) item I’d propose to see addressed in v2 is https://github.com/actions/setup-java/issues/92

[maxim-lobanov]

Thank you for pointing on it. Actually, v2-preview sets path, version and distribution properties: https://github.com/actions/setup-java/blob/v2-preview/src/distributions/base-installer.ts#L125 . I think we need to document it.