Add java plugin with Helidon and Spring Boot skills

[thesurenk]

Summary

• Plugin name: java (one installable plugin)
• Type: remote source
• Source: https://github.com/AI-Coding-Skills/Java-for-Grok.git
• Pinned SHA: 4dbc71cf58e17842b8e8725faa25b83d124afaab
• Homepage: https://github.com/AI-Coding-Skills/Java-for-Grok

This adds one community plugin that bundles two skills:

Skill	Purpose
helidon-best-practices	Helidon 4 SE/MP patterns, H3→H4 migration, runnable SE example
springboot-best-practices	Spring Boot 3.x REST, validation, testing, runnable example

Install: grok plugin install java --trust

Upstream repo: AI-Coding-Skills/Java-for-Grok (Apache-2.0). Skills-only — no hooks, MCP servers, or scripts.

Ownership

• I own this plugin or have the right to distribute it.
• Source repo is under our official org: AI-Coding-Skills.

Checklist

• Added exactly one entry in .grok-plugin/marketplace.json (kebab-case name: java)
• Remote source pins full 40-char lowercase SHA; commit is public and reachable
• Regenerated .grok-plugin/plugin-index.json
• python3 scripts/validate-catalog.py passes
• python3 scripts/generate-plugin-index.py --check passes
• Homepage + description set; upstream has README + .grok-plugin/plugin.json
• License stated upstream (Apache-2.0)

Security

• No RCE, secret exfiltration, or over-broad hooks/MCP
• Network endpoints: none (markdown skills only)
• Credentials: none

Notes for reviewers

Community-maintained Java skills plugin — not affiliated with Oracle/Helidon, Spring, or xAI. Both skills ship in a single plugin package; users install once as java. Runnable examples under examples/helidon-se-customers/ and examples/springboot-customers/. Validates with grok plugin validate upstream.

Test plan

• CI green (catalog validate + index check)
• grok plugin install java --trust
• grok inspect lists both helidon-best-practices and springb