Apache Log4j 2 is an upgrade to Log4j that provides significant improvements over its predecessor, Log4j 1.x, and provides many of the improvements available in Logback while fixing some inherent problems in Logback's architecture.
Log4j 2.4 and greater requires Java 7, versions 2.0-alpha1 to 2.3 required Java 6. Some features require optional dependencies; the documentation for these features specifies the dependencies.
Apache Log4j 2 is distributed under the Apache License, version 2.0.
Issues, bugs, and feature requests should be submitted to the JIRA issue tracking system for this project.
Pull request on GitHub are welcome, but please open a ticket in the JIRA issue tracker first, and mention the JIRA issue in the Pull Request.