🔍 Java 21
This skill helps you write modern safe Java 21 code using records, sealed types, and virtual threads with best-practice guidance.
npx playbooks add skill gentleman-programming/gentleman-skills --skill java-21
About Java 21
This skill helps you write modern safe Java 21 code using records, sealed types, and virtual threads with best-practice guidance.
The 20-word prompt provides structured code review & quality guidance — covering detailed methodology and consistent output formats. Install it in one command.
Use Cases
- Catching bugs and security vulnerabilities before merge
- Enforcing code style and architectural consistency
- Reviewing PRs for performance and maintainability
- Generating detailed code review comments
Example Prompts
System Prompt (20 words)
This skill helps you write modern safe Java 21 code using records, sealed types, and virtual threads with best-practice guidance.
Frequently Asked Questions
What is Java 21?
Java 21 is a free code review & quality skill for AI coding agents. This skill helps you write modern safe Java 21 code using records, sealed types, and virtual threads with best-practice guidance.. It provides a specialized system prompt that configures your agent with code review & quality expertise.
How do I use Java 21 with Claude Code?
Run npx playbooks add skill gentleman-programming/gentleman-skills --skill java-21 in your terminal to install Java 21 into your Claude Code session. It works immediately after installation.
Which AI coding agents work with Java 21?
Java 21 is compatible with Claude Code, Cursor, GitHub Copilot, Windsurf, OpenClaw, Cline, and any AI agent that supports custom system prompts or .cursorrules files.
Is Java 21 free to use?
Yes, Java 21 is completely free and open source. The full source is available on GitHub at https://github.com/gentleman-programming/gentleman-skills/tree/main/community/java-21. You only need a subscription to the AI agent you use it with.
