log4j-gwt is a port of log4j to GWT. Just add it after the normal log4j.jar in your classpath and you are done.
The nice thing is that code will work in and out of an GWT environment without any modifications.
Oh, and you can log any object with log4j. I think the built-in GWT log API is really annoying because there you need to null check and convert to string first.
I agree. Here's the link: http://ej-technologies/jprofiler - if it wasn't for jprofiler, we would need to
run our stuff on 16 servers instead of 3.