Simple Logging Facade for Java (SLF4J)

The Simple Logging Facade for Java (SLF4J) serves as a simple facade or abstraction for various logging frameworks (e.g. java.util.logging, logback, log4j) allowing the end user to plug in the desired logging framework at deployment time.

Before you adopt SLF4J, we recommend that you read the concise SLF4J user manual.

Note that SLF4J-enabling your library implies the addition of only a single mandatory dependency, namely slf4j-api.jar. If no binding/provider is found on the class path, then SLF4J will default to a no-operation implementation.

In case you wish to migrate your Java source files to SLF4J, consider our migrator tool which can migrate your project to use the SLF4J API in just a few minutes.

In case an externally-maintained component you depend on uses a logging API other than SLF4J, such as commons logging, log4j or java.util.logging, have a look at SLF4J's binary-support for legacy APIs.

Donations and support contracts

We welcome your donations to help the SLF4J project. We also offer support contracts. Please contact sales(at) for details.