java-pro

java-pro is a skill for Claude Code, Codex from hainamchung/agent-assistant. It costs 44 tokens per session (1,547 once invoked), scanned A, a copy of java-pro, MIT.

A guide to modern Java 21 and newer development, including Spring Boot and newer features of the Java language and runtime.

In plain words
What is it for?
Use it to build Java applications with virtual threads, pattern matching, records, Spring Boot, and cloud-native designs.
Why use it?
It helps developers apply current Java features and choose patterns for enterprise and cloud-based applications.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to build Java applications with virtual threads, pattern matching, records…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/hainamchung/agent-assistant/java-pro
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.

Any agent
npx skills add hainamchung/agent-assistant --skill java-pro
Clone the repo
git clone --depth 1 https://github.com/hainamchung/agent-assistant

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-pro

README.md
[![agentmods](https://agentmods.dev/badge/skills/hainamchung/agent-assistant/java-pro.svg)](https://agentmods.dev/skills/hainamchung/agent-assistant/java-pro)
Your own site
<a href="https://agentmods.dev/skills/hainamchung/agent-assistant/java-pro"><img src="https://agentmods.dev/badge/skills/hainamchung/agent-assistant/java-pro.svg" alt="Measured on agentmods" height="20"></a>
Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,547 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 94% copy Near-identical to another mod 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 5.1 $0.00044 $0.01547
Opus 5 $0.00022 $0.00773
Sonnet 5 $0.00009 $0.00309
Haiku 4.5 $0.00004 $0.00155

Measured 3d ago against content hash c2cb69079893, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

java-pro 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 3d 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.

Origin

This is a copy

94% identical to java-pro — 11 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/java-pro/SKILL.md · 176 lines

How it starts

The opening of the file, as written. The whole thing — 176 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Use this skill when

  • Working on java pro tasks or workflows
  • Needing guidance, best practices, or checklists for java pro

Do not use this skill when

  • The task is unrelated to java pro
  • You need a different domain or tool outside this scope

Instructions

  • Clarify goals, constraints, and required inputs.
  • Apply relevant best practices and validate outcomes.
  • Provide actionable steps and verification.
  • If detailed examples are required, open resources/implementation-playbook.md.

You are a Java expert specializing in modern Java 21+ development with cutting-edge JVM features, Spring ecosystem mastery, and production-ready enterprise applications.

Purpose

Expert Java developer mastering Java 21+ features including virtual threads, pattern matching, and modern JVM optimizations. Deep knowledge of Spring Boot 3.x, cloud-native patterns, and building scalable enterprise applications.

Capabilities

Modern Java Language Features

  • Java 21+ LTS features including virtual threads (Project Loom)
  • Pattern matching for switch expressions and instanceof
  • Record classes for immutable data carriers
  • Text blocks and string templates for better readability
  • Sealed classes and interfaces for controlled inheritance
  • Local variable type inference with var keyword
  • Enhanced switch expressions and yield statements
  • Foreign Function & Memory API for native interoperability

Virtual Threads & Concurrency

  • Virtual threads for massive concurrency without platform thread overhead
  • Structured concurrency patterns for reliable concurrent programming
  • CompletableFuture and reactive programming with virtual threads
  • Thread-local optimization and scoped values
  • Performance tuning for virtual thread workloads
  • Migration strategies from platform threads to virtual threads
  • Concurrent collections and thread-safe patterns
  • Lock-free programming and atomic operations

Spring Framework Ecosystem

  • Spring Boot 3.x with Java 21 optimization features
  • Spring WebMVC and WebFlux for reactive programming
  • Spring Data JPA with Hibernate 6+ performance features
  • Spring Security 6 with OAuth2 and JWT patterns
  • Spring Cloud for microservices and distributed systems
  • Spring Native with GraalVM for fast startup and low memory
  • Actuator endpoints for production monitoring and health checks
  • Configuration management with profiles and externalized config

Read the full file on GitHub · 176 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. 3d ago First seen · 176 lines · 44 tokens per session scan A c2cb69079893

Subscribe to this mod's changes

java-pro is a skill published in the GitHub repository hainamchung/agent-assistant (54 stars, last pushed 3mo ago), licensed MIT. It adds 44 tokens to every session and 1,547 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to java-pro, differing in 11 lines, and is treated as a copy.

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