# checkstyle/checkstyle

Checkstyle is a development tool to help programmers write Java code that adheres to a coding standard. By default it supports the Google Java Style Guide and Sun Code Conventions, but is highly configurable. It can be invoked with an ANT task and a command line program.

Repository: https://github.com/checkstyle/checkstyle
Canonical: https://ross.abutalabs.com/products/checkstyle
Homepage: https://checkstyle.org
Language: Java
License: LGPL-2.1
License Family: copyleft
Topics: java, static-code-analysis, command-line-tool, static-analysis, code-quality, hacktoberfest
Last push: 2026-08-26T20:35:26+00:00

## Health v2 (maintenance only)
Score: 99/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 98, longevity 100
- inputs: {"age_days": 4751, "days_push": 7, "days_rel": 15, "gap_med": 14, "n_releases_24m": 44}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 9002, forks 4179 (observed 2026-08-28T04:10:26.725848+00:00)

## What it is
Checkstyle is a static analysis tool that checks Java source code against configurable coding standards and style rules, such as naming, imports, Javadoc, formatting, and class design. It ships with a command-line tool and Ant task, supports the Google Java Style Guide and Sun Code Conventions out of the box, and is highly configurable via XML.

## Use cases
- enforce a Java coding standard across a team's codebase
- check Java code style in CI builds
- lint Java code for naming and import violations
- validate Javadoc comments in Java projects
- run Google Java Style checks on my source files
- find style violations like fall-through switches and magic numbers
- integrate code style checking into an Ant or Maven build

## When to choose
- you need automated enforcement of Java coding conventions with highly configurable rules
- you want built-in support for Google Java Style or Sun Code Conventions
- you need a mature, actively maintained Java style checker with CLI and build-tool integration

## When to avoid
- you need a formatter that rewrites code automatically rather than reporting violations (use google-java-format)
- you are linting non-Java languages
- you need deep semantic or bug-detection analysis rather than style checks (use SpotBugs or Error Prone)

## Facets
- artifact type: cli-tool
- maturity: active
- function: linter, static-site-generator, developer-tools
- domain: developer-tools, testing
- platform: jvm, cli, cross-platform
- tags: static-analysis, code-quality, java, coding-standards, style-checker, google-java-style, ant-task, maven-plugin, automation

## Member repositories
- checkstyle/checkstyle (main) score 99

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:26.725848+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:24:21.526661+00:00, confidence not recorded.
  - readme: https://github.com/checkstyle/checkstyle (fetched 2026-08-28T04:10:26.725848+00:00, sha abb50b79dc8e)
  - homepage: https://checkstyle.org (fetched 2026-08-29T08:24:21.956911+00:00, sha 6f097924c7f3)
  - site_page: https://checkstyle.org/apidocs/index.html (fetched 2026-08-29T08:24:21.961744+00:00, sha b9d05297bb53)
  - site_page: https://checkstyle.org/doc_comments_style.html (fetched 2026-08-29T08:24:21.959736+00:00, sha 3152726f02ad)
  - site_page: https://checkstyle.org/checks/javadoc/index.html (fetched 2026-08-29T08:24:21.963589+00:00, sha 8496b1af29ae)
  - site_page: https://checkstyle.org/cmdline.html (fetched 2026-08-29T08:24:21.965364+00:00, sha 2bac2bb586a3)
- Data as of 2026-08-30T08:39:29.467469+00:00.