log4j vs logback

Question

We are using log4j behind a selfmade wrapper. We plan to use much more features of it now.

Should we update to logback ?

(I mean the framework not a facade like SLF4J)

Answer 1

What wrapper do you use?

Answer 2

Not exactly answering your question, but if you could move away from your self-made wrapper then there is Simple Logging Facade for Java (SLF4J) which Hibernate has now switched to (instead of commons logging).

SLF4J suffers from none of the class loader problems or memory leaks observed with Jakarta Commons Logging (JCL).

SLF4J supports JDK logging, log4j and logback. So then it should be fairly easy to switch from log4j to logback when the time is right.

Edit: Aplogies that I hadn't made myself clear. I was suggesting using SLF4J to isolate yourself from having to make a hard choice between log4j or logback.

Answer 3

Your decision should be based on

• your actual need for these "more features"; and
• your expected cost of implementing the change.

You should resist the urge to change APIs just because it's "newer, shinier, better." I follow a policy of "if it's not broken, don't kick it."

If your application requires a very sophisticated logging framework, you may want to consider why.

Answer 4

Logback natively implements the SLF4J API. This means that if you are using logback, you are actually using the SLF4J API. You could theoretically use the internals of the logback API directly for logging, but that is highly discouraged. All logback documentation and examples are written in terms of the SLF4J API.

So by using logback, you'd be actually using SLF4J and if for any reason you wanted to switch back to log4j, you could do so within minutes by simply dropping slf4j-log4j12.jar onto your class path.

Answer 5

Should you? Yes.

Why? Log4J has essentially been deprecated by Logback.

Is it urgent? Maybe not.

Is it painless? Probably, but it may depend on your logging statements.

Note that if you really want to take full advantage of LogBack (or SLF4J), then you really need to write proper logging statements. This will yield advantages like faster code because of the lazy evaluation, and less lines of code because you can avoid guards.

Finally, I highly recommend SLF4J. (Why recreate the wheel with your own facade?)