# apache/logging-log4j2

Apache Log4j is a versatile, feature-rich, efficient logging API and backend for Java.

Repository: https://github.com/apache/logging-log4j2
Canonical: https://ross.abutalabs.com/products/logging-log4j2
Homepage: https://logging.apache.org/log4j/2.x
Language: Java
License: Apache-2.0
License Family: permissive
Topics: logging, apache, api, java, library, log4j, log4j2, jvm, logger, syslog
Last push: 2026-08-21T16:56:41+00:00

## Health v2 (maintenance only)
Score: 92/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 98, release rhythm 80, longevity 100
- inputs: {"age_days": 4830, "days_push": 12, "days_rel": 58, "gap_med": 41.0, "n_releases_24m": 13}
- flags: no_readme
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3614, forks 1733 (observed 2026-08-28T04:08:11.729598+00:00)

## What it is
Apache Log4j 2 is an industrial-grade Java logging framework consisting of a feature-rich logging API (Log4j API) and a high-performance implementation (Log4j Core). It supports appenders for files, sockets, databases, and SMTP, multiple output layouts, filters, lookups, hot config reloading, and extensive plugin-based extensibility.

## Use cases
- add structured logging to a Java application
- replace System.out.println with a proper logging framework
- route logs from SLF4J or JUL to a single backend
- write logs to files, databases, or syslog in Java
- configure log levels and formats via log4j2.xml
- use Log4j Core as the logging backend in Spring Boot
- migrate from Log4j 1 or Logback

## When to choose
- you need a mature, actively maintained logging backend for JVM applications
- you want a logging facade with rich message types and lambda support
- you need high-throughput, garbage-collector-friendly logging
- you need flexible appenders, layouts, and filters out of the box

## When to avoid
- you are not on the JVM platform
- you need a minimal zero-dependency logging solution
- your project is locked to Log4j 1.x APIs without migration effort

## Facets
- artifact type: library
- maturity: stable
- function: logging, monitoring, plugin-system
- domain: developer-tools, backend, monitoring
- platform: jvm, cross-platform
- tags: log4j2, logging-framework, java, apache, slf4j, appender, log-configuration

## Member repositories
- apache/logging-log4j2 (main) score 92

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:11.729598+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 2026-08-29T18:33:36.444653+00:00, confidence not recorded.
  - homepage: https://logging.apache.org/log4j/2.x (fetched 2026-08-29T09:26:44.653239+00:00, sha dca5bef83745)
  - site_page: https://logging.apache.org/log4j/2.x/manual/getting-started.html (fetched 2026-08-29T09:26:44.656585+00:00, sha 0d9fb104b1ba)
  - site_page: https://logging.apache.org/log4j/2.x/manual/installation.html (fetched 2026-08-29T09:26:44.659356+00:00, sha 54a4a3d4de68)
  - site_page: https://logging.apache.org/log4j/2.x/faq.html (fetched 2026-08-29T09:26:44.661770+00:00, sha 96eee4cc17d1)
- Data as of 2026-08-30T08:39:29.467469+00:00.