java-final-field-mutation

Use when Java 26+ code mutates `final` fields with deep reflection, serialization frameworks, JNI, or Unsafe.

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Works with Claude Code, Claude apps, Codex, Cursor, Gemini CLI, GitHub Copilot, VS Code, OpenCode, Goose, Windsurf. Read the repository before you give any tool access to your data.

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Use when Java 26+ code mutates `final` fields with deep reflection, serialization frameworks, JNI, or Unsafe.

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What this skill can do and what it asks for, from its SKILL.md. Checked Oct 25, 2026.

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codeload.github.com · found in install command

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~/.claude/skills/java-final-field-mutation

What's inside

Skill name: java-final-field-mutation
Description: Use when Java 26+ code mutates `final` fields with deep reflection, serialization frameworks, JNI, or Unsafe.
License: MIT
Compatibility: JDK 26+
Instructions: 25 lines in SKILL.md · view on GitHub

Files (2)

SKILL.md
jep-500.md · examples/

SKILL.md (first lines)

# Prepare to Make Final Mean Final

Use for **Prepare to Make Final Mean Final** work from [JEP 500](https://openjdk.org/jeps/500) when targeting JDK 26+.

## When active

- Find `Field.setAccessible(true)` plus `Field.set(...)` on final fields.
- Prefer constructors, factories, builders, records, or supported serialization paths.
- Use `--illegal-final-field-mutation=debug|deny` to locate and harden offenders.

## Pitfalls

- `--add-opens` alone does not enable final-field mutation.
- Warnings are per mutating module by default.
- Startup opt-in belongs to the application owner, not a hidden library requirement.

## Examples

Read `examples/jep-500.md` for JEP-derived snippets.

## References

- https://openjdk.org/jeps/500

From isp-insoft-gmbh/isp-insoft-ai-skills, MIT.

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Last commit (this folder): Sep 7, 2026 (1 month ago)

From GitHub (fetched Oct 24, 2026).

Details

License: MIT
Repository: github.com/isp-insoft-gmbh/isp-insoft-ai-skills
First seen: Oct 24, 2026
Last checked: Oct 24, 2026
Source: GitHub github-graphql

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java-final-field-mutation skill. Agent Mart. https://agentmart.dev/skills/isp-insoft-gmbh-java-final-field-mutation (last updated 2026-10-24)