Modernize with Java 17 features and improve performance

[gounthar]

What feature do you want to see added?

Looking at jenkinsci/embeddable-build-status-plugin#419, I'm wondering if:

• This kind of change is already part of our UpgradeNextMajorParentVersion recipe
• If not, then shouldn't we add, as in the linked PR:
  • Modernize collection initialization using Java 17's Map.of() for better performance
  • Convert instance-level HashMap initializers to static final immutable maps
  • Add proper null safety handling for immutable map usage

Upstream changes

No response

Are you interested in contributing this feature?

No response

[viru0909-dev]

Hi @gounthar, I am interested in picking this up!

I've reviewed the requirements and the linked precedent (issue #419 in embeddable-build-status-plugin). I have my environment set up with Java 21 (as required by the README) and am ready to proceed.

Could you briefly clarify the primary scope?

1.Internal Refactoring: Is the goal to refactor this tool's own source code (using Java 17+ features like Map.of and instanceof) to improve its performance and maintainability?

2.Recipe Configuration: Or is the goal to configure/expose the UpgradeToJava17 OpenRewrite recipe so it can be applied to other plugins?

I assume it is internal refactoring (Option 1) given the project context, but I wanted to confirm before opening a PR.