This is the first release of Log4j 2 and is being made available to get feedback from the community.
Some of the features and improvements in Log4j 2 are:
* API Separation - The API for Log4j is separate from the implementation. It is now clear to application
developers what classes and methods they can use with compatibility being assured, while also
allowing improvements to be made to the implementation.
* Designed for Audit Logging - Unlike Log4j 1.x and Logback, Log4j 2 will not lose events during
reconfiguration. Log4j 2 also supports Messages, which easily allow audit events to be flow through
* Improved Performance - Faster performance than Log4j 1.x in critical areas and similar performance
to Logback in most circumstances.
* Support for multiple APIs - While the Log4j 2 API will provide the best performance, support for SLF4J
and Commons Logging APIs are provided.
* Automatic Reloading of Configurations - Like Logback, Log4j 2 supports filtering based on context data,
markers, regular expressions and other components in the Log event and can be specified to apply
to all events before being passed to Loggers or as they pass through Appenders. In addition, filters
can also be associated with Loggers, Unlike Logback, a common Filter class can be used in any
of these circumstances. Log4j 2 currently supports configuration via XML or JSON.
* Plugin Architecture - All configurable components are defined as Log4j plugins. As such, no
Log4j code must be changed to create a new Appender, Layout, Pattern Converter, etc.
Log4j will automatically recognize properly defined plugins and use them when they are
referenced in the configuration.
* Property Support - Properties can be referenced in the configuration and either be directly
replace or passed to the underlying component where they can be dynamically resolved.
Properties can come from values defined in the configuration file, system properties,
environment variables, the ThreadContext Map, and data present in the event. Users can
further customize the property providers by adding their own Lookup Plugin
Apache log4j 2.0 requires JDK 5 or later.