slf4jlog4j12

slf4j-log4j12 is a binding in the SLF4J project that routes calls made through the SLF4J API to the Apache Log4j version 1.2 backend. By including this binding on the classpath along with the SLF4J API and a Log4j 1.2 installation, a Java application can use the SLF4J facade while the actual logging is performed by Log4j 1.2. The binding implements the SLF4J binding interface and forwards each log event to the corresponding Log4j logger, preserving the logger name and level.

Usage typically involves adding the slf4j-log4j12 artifact to the project in addition to slf4j-api and a Log4j 1.2 library. Log4j configuration is then controlled via standard Log4j configuration files such as log4j.properties or log4j.xml. When configuring, you specify log levels, appenders, and formatting through Log4j’s own configuration.

Compatibility and considerations: this binding is intended for projects that still rely on Log4j 1.2, which has reached end of life and is no longer actively maintained. For new projects, consider using a more modern backend such as Log4j 2 or another supported framework, and ensure that the chosen SLF4J binding matches both the API and the backend. Only one SLF4J binding should be present on the classpath to avoid binding conflicts; if multiple bindings are detected, SLF4J will report a warning and may pick one binding at runtime.