Agent skill

Java Coding Standards

Spring Bootサービス向けのJavaコーディング標準：命名、不変性、Optional使用、ストリーム、例外、ジェネリクス、プロジェクトレイアウト。

Install Java Coding Standards

skills CLI

$ npx skills add affaan-m/ECC --skill java-coding-standards -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install affaan-m/ECC java-coding-standards --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/affaan-m/ECC.git skills-src && mkdir -p .claude/skills && cp -r skills-src/docs/ja-JP/skills/java-coding-standards .claude/skills/java-coding-standards && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "java-coding-standards" agent skill from https://github.com/affaan-m/ECC/tree/main/docs/ja-JP/skills/java-coding-standards into .claude/skills/java-coding-standards/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-coding-standards", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/affaan-m/ECC/tree/main/docs/ja-JP/skills/java-coding-standards

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add affaan-m/ECC --skill java-coding-standards -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install affaan-m/ECC java-coding-standards --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/affaan-m/ECC.git skills-src && mkdir -p .agents/skills && cp -r skills-src/docs/ja-JP/skills/java-coding-standards .agents/skills/java-coding-standards && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "java-coding-standards" agent skill from https://github.com/affaan-m/ECC/tree/main/docs/ja-JP/skills/java-coding-standards into .agents/skills/java-coding-standards/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-coding-standards", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add affaan-m/ECC --skill java-coding-standards -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install affaan-m/ECC java-coding-standards --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/affaan-m/ECC.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/docs/ja-JP/skills/java-coding-standards .cursor/skills/java-coding-standards && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "java-coding-standards" agent skill from https://github.com/affaan-m/ECC/tree/main/docs/ja-JP/skills/java-coding-standards into .cursor/skills/java-coding-standards/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-coding-standards", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/affaan-m/ECC.git --path docs/ja-JP/skills/java-coding-standards

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add affaan-m/ECC --skill java-coding-standards -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install affaan-m/ECC java-coding-standards --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/affaan-m/ECC.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/docs/ja-JP/skills/java-coding-standards .gemini/skills/java-coding-standards && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "java-coding-standards" agent skill from https://github.com/affaan-m/ECC/tree/main/docs/ja-JP/skills/java-coding-standards into .gemini/skills/java-coding-standards/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-coding-standards", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install affaan-m/ECC java-coding-standards

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add affaan-m/ECC --skill java-coding-standards -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/affaan-m/ECC.git skills-src && mkdir -p .github/skills && cp -r skills-src/docs/ja-JP/skills/java-coding-standards .github/skills/java-coding-standards && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "java-coding-standards" agent skill from https://github.com/affaan-m/ECC/tree/main/docs/ja-JP/skills/java-coding-standards into .github/skills/java-coding-standards/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-coding-standards", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add affaan-m/ECC --skill java-coding-standards -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install affaan-m/ECC java-coding-standards --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/affaan-m/ECC.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/docs/ja-JP/skills/java-coding-standards .opencode/skills/java-coding-standards && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "java-coding-standards" agent skill from https://github.com/affaan-m/ECC/tree/main/docs/ja-JP/skills/java-coding-standards into .opencode/skills/java-coding-standards/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "java-coding-standards", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: java-coding-standards
GitHub stars: 274k
Used in: 2 other repos
Token cost: ~668 tokens
SKILL.md length: 60 words
Files: 1
Skills in repo: 657
Repo updated: Oct 5, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Spring Bootサービス向けのJavaコーディング標準：命名、不変性、Optional使用、ストリーム、例外、ジェネリクス、プロジェクトレイアウト。

Tasks that involve Code quality
SKILL.md covers 核となる原則, 命名, 不変性 and Optionalの使用, plus 9 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
Tasks that involve Backend development

What it does

Java Coding Standards is an agent skill from affaan-m/ECC. Spring Bootサービス向けのJavaコーディング標準：命名、不変性、Optional使用、ストリーム、例外、ジェネリクス、プロジェクトレイアウト。

Its SKILL.md is about 670 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Backend & APIs, covering Code quality and Backend development. It works with Java and Spring Boot. The repository describes itself as: The agent harness performance optimization system. Skills, instincts, memory, security, and research-first development for Claude Code, Codex, Opencode, Cursor and beyond. The licence is MIT.

When your agent uses it

Tasks that involve Code quality
Tasks that involve Backend development

Example prompts

“/java-coding-standards”

What it can do on your machine

Read from SKILL.md and the folder at commit ef648e0. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are java).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Java Coding Standards loads about 668 tokens when it runs. Until then it costs about 25 tokens; SKILL.md has 60 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~25
When it runs · the whole SKILL.md, loaded when a task matches: ~668

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from affaan-m/ECC at commit ef648e0, republished under its MIT licence (© affaan-m). 60 words, ~668 tokens.

Download SKILL.mdSave it as .claude/skills/java-coding-standards/SKILL.md (or your agent's skills folder).

name: java-coding-standards
description: Spring Bootサービス向けのJavaコーディング標準：命名、不変性、Optional使用、ストリーム、例外、ジェネリクス、プロジェクトレイアウト。

Javaコーディング標準

Spring Bootサービスにおける読みやすく保守可能なJava(17+)コードの標準。

核となる原則

巧妙さよりも明確さを優先
デフォルトで不変; 共有可変状態を最小化
意味のある例外で早期失敗
一貫した命名とパッケージ構造

命名

java

// PASS: クラス/レコード: PascalCase
public class MarketService {}
public record Money(BigDecimal amount, Currency currency) {}

// PASS: メソッド/フィールド: camelCase
private final MarketRepository marketRepository;
public Market findBySlug(String slug) {}

// PASS: 定数: UPPER_SNAKE_CASE
private static final int MAX_PAGE_SIZE = 100;

不変性

java

// PASS: recordとfinalフィールドを優先
public record MarketDto(Long id, String name, MarketStatus status) {}

public class Market {
  private final Long id;
  private final String name;
  // getterのみ、setterなし
}

Optionalの使用

java

// PASS: find*メソッドからOptionalを返す
Optional<Market> market = marketRepository.findBySlug(slug);

// PASS: get()の代わりにmap/flatMapを使用
return market
    .map(MarketResponse::from)
    .orElseThrow(() -> new EntityNotFoundException("Market not found"));

ストリームのベストプラクティス

java

// PASS: 変換にストリームを使用し、パイプラインを短く保つ
List<String> names = markets.stream()
    .map(Market::name)
    .filter(Objects::nonNull)
    .toList();

// FAIL: 複雑なネストされたストリームを避ける; 明確性のためにループを優先

例外

ドメインエラーには非チェック例外を使用; 技術的例外はコンテキストとともにラップ
ドメイン固有の例外を作成(例: MarketNotFoundException)
広範なcatch (Exception ex)を避ける(中央でリスロー/ログ記録する場合を除く)

java

throw new MarketNotFoundException(slug);

ジェネリクスと型安全性

生の型を避ける; ジェネリックパラメータを宣言
再利用可能なユーティリティには境界付きジェネリクスを優先

java

public <T extends Identifiable> Map<Long, T> indexById(Collection<T> items) { ... }

プロジェクト構造(Maven/Gradle)

src/main/java/com/example/app/
  config/
  controller/
  service/
  repository/
  domain/
  dto/
  util/
src/main/resources/
  application.yml
src/test/java/... (mainをミラー)

フォーマットとスタイル

一貫して2または4スペースを使用(プロジェクト標準)
ファイルごとに1つのpublicトップレベル型
メソッドを短く集中的に保つ; ヘルパーを抽出
メンバーの順序: 定数、フィールド、コンストラクタ、publicメソッド、protected、private

避けるべきコードの臭い

長いパラメータリスト → DTO/ビルダーを使用
深いネスト → 早期リターン
マジックナンバー → 名前付き定数
静的可変状態 → 依存性注入を優先
サイレントなcatchブロック → ログを記録して行動、または再スロー

ログ記録

java

private static final Logger log = LoggerFactory.getLogger(MarketService.class);
log.info("fetch_market slug={}", slug);
log.error("failed_fetch_market slug={}", slug, ex);

Null処理

やむを得ない場合のみ@Nullableを受け入れる; それ以外は@NonNullを使用
入力にBean Validation(@NotNull、@NotBlank)を使用

テストの期待

JUnit 5 + AssertJで流暢なアサーション
モック用のMockito; 可能な限り部分モックを避ける
決定論的テストを優先; 隠れたsleepなし

覚えておく: コードを意図的、型付き、観察可能に保つ。必要性が証明されない限り、マイクロ最適化よりも保守性を最適化します。

Files

Just SKILL.md in docs/ja-JP/skills/java-coding-standards of affaan-m/ECC.

Open the folder on GitHubat commit ef648e0

Used in 2 other repositories

We found 2 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 2 other GitHub owners. This page covers the copy in affaan-m/ECC, which our catalogue first saw on October 7, 2026.

Compare with similar skills

Java Coding Standards next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Java Coding Standards compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Java Coding Standards this skillaffaan-m/ECC	274k	2 repos	~668	Automated safety check: Pass	MIT	2 days ago
Java Coding Standardsxu-xiang/everything-claude-code-zh	2k	—	~676	Automated safety check: Pass	MIT	7 mo ago
Java Coding StandardsSnailclimb/AIGuide	667	—	~1k	Automated safety check: Pass	None	3 mo ago
Java Coding Standardsvibeeval/vibecosystem	531	3 repos	~877	Automated safety check: Pass	MIT	1 mo ago
Java Coding Standardsxu-xiang/everything-claude-code-zh	2k	—	~779	Automated safety check: Pass	MIT	7 mo ago
Java Rulessoftspark/ai-toolkit	179	—	~3.1k	Automated safety check: Pass	Apache-2.0	today

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Questions about Java Coding Standards

What does Java Coding Standards do?

Spring Bootサービス向けのJavaコーディング標準：命名、不変性、Optional使用、ストリーム、例外、ジェネリクス、プロジェクトレイアウト。. Java Coding Standards is an agent skill from affaan-m/ECC.

When should I use Java Coding Standards?

Java Coding Standards fits situations like: tasks that involve Code quality; tasks that involve Backend development.

How do I install Java Coding Standards in Claude Code?

Run `npx skills add affaan-m/ECC --skill java-coding-standards -a claude-code`. Or copy the skill folder (docs/ja-JP/skills/java-coding-standards in affaan-m/ECC) into .claude/skills/java-coding-standards in your project. Claude Code loads it when a task matches its description.

How do I install Java Coding Standards in Codex?

Run `npx skills add affaan-m/ECC --skill java-coding-standards -a codex`. Or copy the skill folder (docs/ja-JP/skills/java-coding-standards in affaan-m/ECC) into .agents/skills/java-coding-standards in your project. Codex loads it when a task matches its description.

Can I use Java Coding Standards in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add affaan-m/ECC --skill java-coding-standards -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/java-coding-standards, .gemini/skills/java-coding-standards, .github/skills/java-coding-standards and .opencode/skills/java-coding-standards in your project.

What does Java Coding Standards need to run?

SKILL.md names no scripts, command-line tools or credentials: Java Coding Standards is instructions for the agent only.

Does Java Coding Standards access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Java Coding Standards safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Java Coding Standards use?

Java Coding Standards is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Java Coding Standards use?

About 668 tokens (SKILL.md is roughly 2.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Java Coding Standards?

Skills that share tags, products or a category with Java Coding Standards: Java Coding Standards (xu-xiang/everything-claude-code-zh, 2k stars), Java Coding Standards (Snailclimb/AIGuide, 667 stars), Java Coding Standards (vibeeval/vibecosystem, 531 stars) and Java Coding Standards (xu-xiang/everything-claude-code-zh, 2k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Java Coding Standards?

affaan-m (a GitHub user) maintains it in affaan-m/ECC, which has 274,360 GitHub stars. The repository holds 657 skills in this directory. The repository was last updated on October 5, 2026.

Source: affaan-m/ECC on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Java Coding Standards

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Javaコーディング標準

核となる原則

命名

不変性

Optionalの使用

ストリームのベストプラクティス

例外

ジェネリクスと型安全性

プロジェクト構造(Maven/Gradle)

フォーマットとスタイル

避けるべきコードの臭い

ログ記録

Null処理

テストの期待

Files

Used in 2 other repositories

Compare with similar skills

Similar skills

More from affaan-m/ECC

Related

Questions about Java Coding Standards