Difference between slf4j-log4j12 and log4j-over-slf4j

java log4j slf4j
Kumar Sambhav picture Kumar Sambhav · Jun 25, 2015 · Viewed 32.8k times · Source

What's the difference between slf4j-log4j12 and log4j-over-slf4j and when should each be used?

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>1.7.12</version>
</dependency>
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>log4j-over-slf4j</artifactId>
    <version>1.7.12</version>
</dependency>

Answer

Puce picture Puce · Jun 25, 2015 
log4j-over-slf4j

Use this if your code or some libraries you are using uses Log4j directly, but you want to use a different SLF4J binding than Log4j. It will route the Log4j API calls to SLF4J to the binding you choose. You need to remove the Log4j library from your classpath and replace it with this dependency.

slf4j-log4j12

Use this if you want to use the Log4j 1.2 binding for SLF4J.

You shouldn't use both of these libraries at the same time.

Please note also that Log4j 2 has been released.

Related questions

Configuring Log4j Loggers Programmatically

I am trying to use SLF4J (with log4j binding) for the first time. I would like to configure 3 different named Loggers that can be returned by a LoggerFactory which will log different levels and push the messages to …

Read More
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". in a Maven Project

I have a dependency for SLF4J. I am getting this error: SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". SLF4J: Defaulting to no-operation (NOP) logger implementation SLF4J: See http://www.slf4j.org/codes.…

Read More
Setting log level of message at runtime in slf4j

When using log4j, the Logger.log(Priority p, Object message) method is available and can be used to log a message at a log level determined at runtime. We're using this fact and this tip to redirect stderr to …

Read More