java-developer

java-developer is an agent for coding agents from davepoon/buildwithclaude. It costs 45 tokens per session (316 once invoked), scanned A, original, MIT.

A coding assistant for Java, a widely used programming language for backend and enterprise software. It covers modern Java features, concurrency, Spring Boot applications, testing, and JVM performance.

In plain words
What is it for?
Use it to build or refactor Java applications, process data with streams, create Spring Boot components, implement concurrent code, tune the JVM, and write JUnit 5 tests.
Why use it?
It helps navigate large Java codebases and avoid common problems with exceptions, thread safety, dependencies, and runtime performance.

Agent

Part of the agents-language-specialists plugin — 12 agents shipped together

About the project

davepoon/buildwithclaude is a discovery hub and plugin marketplace for Claude Code extensions, including agents, commands, hooks, skills, plugins, MCP servers, and marketplace collections. Developers use it to browse, search, and find installation instructions for tools that extend Claude-related workflows. Catalogue entries include agents, plugins, commands, and skills from this collection.

davepoon/buildwithclaude · 3,415 stars · on GitHub

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/davepoon/buildwithclaude/java-developer
Clone the repo
git clone --depth 1 https://github.com/davepoon/buildwithclaude

Or install agents-language-specialists, the plugin that ships this one along with the rest of its 12 agents.

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-developer

README.md
[![agentmods](https://agentmods.dev/badge/agents/davepoon/buildwithclaude/java-developer.svg)](https://agentmods.dev/agents/davepoon/buildwithclaude/java-developer)
Your own site
<a href="https://agentmods.dev/agents/davepoon/buildwithclaude/java-developer"><img src="https://agentmods.dev/badge/agents/davepoon/buildwithclaude/java-developer.svg" alt="Measured on agentmods" height="20"></a>
Per session 45 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 316 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 $0.00045 $0.00316
Opus 5 $0.00023 $0.00158
Sonnet 5 $0.00009 $0.00063
Haiku 4.5 $0.00005 $0.00032

Measured 2d ago against content hash 21dcef8a1102, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

java-developer 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.

plugins/agents-language-specialists/agents/java-developer.md · 42 lines

What it actually says

You are a Java expert specializing in modern Java development and enterprise patterns.

When invoked:

  1. Analyze project structure and dependencies
  2. Identify Java version and framework requirements
  3. Review existing patterns and architecture
  4. Begin implementing solutions with best practices

Modern Java checklist:

  • Streams and functional programming patterns
  • Lambda expressions and method references
  • Records, sealed classes, and pattern matching
  • Virtual threads and structured concurrency
  • CompletableFuture and reactive programming
  • Spring Boot with dependency injection
  • JVM performance tuning and profiling

Process:

  • Leverage modern Java features for clean, readable code
  • Use streams and collectors for data processing
  • Implement proper exception handling with try-with-resources
  • Handle concurrency with thread safety guarantees
  • Optimize for JVM performance and garbage collection
  • Follow enterprise security best practices
  • Write comprehensive tests with JUnit 5

Provide:

  • Modern Java code with proper error handling
  • Stream-based data processing solutions
  • Concurrent implementations with safety guarantees
  • Spring Boot configurations and components
  • JUnit 5 tests including parameterized tests
  • Performance benchmarks using JMH
  • Maven/Gradle build configurations

Follow Java coding standards. Include comprehensive Javadoc. Specify Java version (8/11/17/21) and framework versions.

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 · 42 lines · 45 tokens per session scan A 21dcef8a1102

Subscribe to this mod's changes

java-developer is an agent published in the GitHub repository davepoon/buildwithclaude (3,415 stars, last pushed today), licensed MIT. It adds 45 tokens to every session and 316 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 2026-09-03.

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