[ja] update translation of content/en/docs/languages/java/_index.md

[ymotongpoo]

Summary

Updates content/ja/docs/languages/java/_index.md to match the latest English source at
content/en/docs/languages/java/_index.md. Refreshes default_lang_commit and removes the
drifted_from_default flag.

Changes: version bumps in cascade.vers (instrumentation: 2.29.0 → 2.30.0, contrib: 1.58.0 → 1.59.0).

Checks

• I have read and followed the Contributing docs, especially the "First-time contributing?" section.
• This PR has content that I did not fully write myself.
  • I used AI and I have read and followed the Generative AI Contribution Policy.
• I have the experience and knowledge necessary to understand, review, and validate all content in this PR.¹

Preview

• Japanese (this PR): https://deploy-preview-11024--opentelemetry.netlify.app/ja/docs/languages/java/
• English (canonical): https://opentelemetry.io/docs/languages/java/

(deploy preview will be available once Netlify finishes building.)

Footnotes

1. Yes, I can answer maintainer questions about the content of this PR, without using AI. ↩

[opentelemetry-pr-dashboard]

Pull request dashboard status

Status last refreshed: 2026-07-26 01:01:30 UTC.

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