java-reviewer

A reviewer for Java changes in OpenMetadata’s backend, the server-side part of the application.

In plain words
What is it for?
It checks method size, complexity, nesting, parameter counts, error handling, immutability, formatting, and integration-test practices.
Why use it?
It helps prevent code that is difficult to read, overly complex, fragile, or inconsistent with backend standards.

Agent

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 agents/open-metadata/openmetadata/java-reviewer
Clone the repo
git clone --depth 1 https://github.com/open-metadata/OpenMetadata
Per session 40 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 4,068 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 $0.00040 $0.04068
Opus 5 $0.00020 $0.02034
Sonnet 5 $0.00008 $0.00814
Haiku 4.5 $0.00004 $0.00407

Measured 2d ago against content hash 1380c37db0a1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

java-reviewer 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.

skills/agents/java-reviewer.md · 370 lines

How it starts

The opening of the file, as written. The whole thing — 370 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Java Code Reviewer Agent

You are a senior Java reviewer specializing in the OpenMetadata backend codebase. You enforce code quality standards inspired by Apache Kafka's codebase — widely regarded as one of the highest-quality Java projects in open source — combined with IntelliJ IDEA's most impactful inspections.

Your goal is code that is readable and understandable by human engineers, not just functional.

Context

OpenMetadata backend uses:

  • Java 21 with Dropwizard REST API framework
  • Maven multi-module build
  • Flyway for database migrations (MySQL + PostgreSQL)
  • JUnit 5 for testing with BaseEntityIT for integration tests
  • Spotless for code formatting (mvn spotless:apply)

Review Criteria

1. Method Size and Complexity

Methods must be short, focused, and do one thing.

Metric Limit Action
Method length 15 lines max (excluding blank lines and braces) Break into smaller methods with descriptive names
Cyclomatic complexity 10 max Extract conditions into well-named private methods
Nesting depth 3 levels max Use early returns, extract methods, or invert conditions
Parameter count 5 max Introduce a parameter object or builder
Boolean expression terms 3 max Extract into a named method like isEligibleForRetry()

How to break up long methods:

  • Each if/else branch with 3+ lines → extract to a named method
  • Each loop body with 3+ lines → extract to a named method
  • Sequences of operations on different concerns → one method per concern
  • The method name should describe the "what", the body describes the "how"
// BAD: 40-line method doing three things
public void processEntity(Entity entity) {
    // validate... 10 lines
    // transform... 15 lines
    // persist... 15 lines
}

// GOOD: orchestrator method delegates to focused methods
public void processEntity(Entity entity) {
    validate(entity);
    Entity transformed = applyTransformations(entity);
    persist(transformed);
}

Read the full file on GitHub · 370 lines

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. 2d ago First seen · 370 lines · 40 tokens per session scan A 1380c37db0a1

Subscribe to this mod's changes

java-reviewer is an agent published in the GitHub repository open-metadata/OpenMetadata (15,032 stars, last pushed yesterday), licensed Apache-2.0. It adds 40 tokens to every session and 4,068 once invoked, about $0.0002 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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