java-conventions

java-conventions is a skill for Claude Code, Codex from Goldziher/ai-rulez. It costs 50 tokens per session (353 once invoked), scanned A, original, MIT.

A set of rules for modern Java development, covering code structure, builds, testing, performance checks, exceptions, and dependency security.

In plain words
What is it for?
Use it when creating or reviewing Java 17 or newer applications and libraries, including Maven or Gradle builds, JUnit tests, records, sealed classes, and benchmarks.
Why use it?
It helps prevent resource leaks, overly broad error handling, mutable shared state, inconsistent builds, and vulnerable dependencies.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/goldziher/ai-rulez/java-conventions
Any agent
npx skills add Goldziher/ai-rulez --skill java-conventions
Clone the repo
git clone --depth 1 https://github.com/Goldziher/ai-rulez

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for java-conventions

README.md
[![agentmods](https://agentmods.dev/badge/skills/goldziher/ai-rulez/java-conventions.svg)](https://agentmods.dev/skills/goldziher/ai-rulez/java-conventions)
Your own site
<a href="https://agentmods.dev/skills/goldziher/ai-rulez/java-conventions"><img src="https://agentmods.dev/badge/skills/goldziher/ai-rulez/java-conventions.svg" alt="Measured on agentmods" height="20"></a>
Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 353 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What 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.

ModelPer sessionOnce invoked
Fable 5 $0.00050 $0.00353
Opus 5 $0.00025 $0.00177
Sonnet 5 $0.00010 $0.00071
Haiku 4.5 $0.00005 $0.00035

Measured 4d ago against content hash 7ae8a05a20cf, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

java-conventions 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 4d 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.

internal/builtins/languages/java/skills/java-conventions/SKILL.md · 18 lines

What it actually says

  • Java 17+ LTS, records for immutable data, sealed classes for restricted hierarchies, pattern matching.
  • A consistent style guide and auto-formatter (e.g., Google Java Style + google-java-format). Static analysis (e.g., Error Prone + SpotBugs).
  • Build: Maven or Gradle with wrapper scripts (mvnw/gradlew). Commit wrapper files.
  • Testing: JUnit 5 with @ParameterizedTest, an assertion library (e.g., AssertJ), a coverage tool (e.g., JaCoCo) at 80%+.
  • Benchmarking: JMH for microbenchmarks — never use System.nanoTime() loops.
  • Error handling: specific exceptions only, never catch (Exception), use try-with-resources for AutoCloseable.
  • var for obvious types, Optional<T> for returns (never params/fields), final fields by default.
  • Prefer constructor injection over field injection for DI. Immutable collections: List.of(), Map.of().
  • Streams for collection transforms, instanceof pattern matching, switch expressions.
  • Security: OWASP dependency-check Maven/Gradle plugin for CVE scanning.
  • Dependencies: commit lock files, use BOM for version alignment, avoid SNAPSHOT in releases.
  • Anti-patterns: public fields, mutable static state, raw types, checked exceptions in lambdas.
Changes

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.

  1. 4d ago First seen · 18 lines · 50 tokens per session scan A 7ae8a05a20cf

Subscribe to this mod's changes

java-conventions is a skill published in the GitHub repository Goldziher/ai-rulez (140 stars, last pushed 4d ago), licensed MIT. It adds 50 tokens to every session and 353 once invoked, about $0.0003 per session on Opus 5. 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 2026-08-30.

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