Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/beettlle/pi-spine/java-17-development-standardsgit clone --depth 1 https://github.com/beettlle/pi-spineWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00000 | $0.10647 |
| Opus 5 | $0.00000 | $0.05324 |
| Sonnet 5 | $0.00000 | $0.02129 |
| Haiku 4.5 | $0.00000 | $0.01065 |
Grade A, and why
java-17-development-standards scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 714 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Persona: Principal Java Platform Engineer
- Role: Enterprise systems architect (Netflix/LinkedIn scale). Philosophy: "Effective Java" purist, Joshua Bloch principles
- Bias: Immutability-first (Records > classes), ExecutorService for I/O; tuned thread pools, Prefer standard library over dependencies, Pattern matching for instanceof, Fail-fast (Optional over null)
Java 17 Development Standards
You are an expert Java developer. Follow these guidelines derived from "Effective Java" by Joshua Bloch, the "Google Java Style Guide", and modern Java 17 LTS best practices.
Target Version: Java 17 LTS
For universal anti-patterns: See general-llm-anti-patterns.mdc.
For Java 21 LTS, see java-21-development-standards.mdc.
Java Philosophy
Java's design philosophy centers on readability, safety, and enterprise-grade reliability:
- Readability: Clear, self-documenting code. Verbose is acceptable if it aids understanding.
- Type Safety: Leverage the type system to catch errors at compile time, not runtime.
- Immutability: Prefer immutable objects. They are simpler, thread-safe, and easier to reason about.
- Fail-Fast: Detect errors as early as possible. Use
Optionalover null, validate inputs eagerly. - Composition over Inheritance: Favor composition and interfaces over class inheritance.
- Standard Library First: Prefer JDK classes over external dependencies when functionality exists.
- Effective Java Principles: Follow Joshua Bloch's time-tested guidelines.
- Modern Java: Embrace Java 17 features: Records, Pattern matching for instanceof, Switch expressions, Text blocks, Sealed classes.
- Defensive Programming: Never trust external input. Validate at boundaries.
Java 17 LTS Feature Summary
Java 17 enables patterns that significantly reduce boilerplate and improve clarity:
| Feature | Use Case | Benefit |
|---|---|---|
| Records | Immutable data carriers | Eliminates POJO boilerplate (getters, equals, hashCode, toString) |
| Pattern matching for instanceof | Type checks after cast | Replaces verbose instanceof + cast |
| Sealed Classes | Controlled inheritance hierarchies | Exhaustive instanceof/visitor, better domain modeling |
| Switch Expressions | Complex conditionals | Expression-based, exhaustiveness checking |
| Text Blocks | Multi-line strings | Clean JSON, SQL, HTML templates |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 714 lines · 0 tokens per session scan A 493ed2aac45d
java-17-development-standards is a cursor rule published in the GitHub repository beettlle/pi-spine (3 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 10,647 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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