The fact that
java.util.loggingmade it into the JRE does not make it any better than it is, so there's a good reason to hide it behind a facade and never use it directly. But there is no reason for everyone to invent their own logging facades instead of simply using SLF4J.
In my own applications, I always use SLF4J with Logback. Working with Tomcat, this means I'm getting an ugly mixture of log messages in different formats from my web application logging to System.out with Logback, and from Tomcat itself logging to System.err via JULI and java.util.logging, not to mention any third-party libraries contained in my application which use log4j, Apache Commons Logging or whatever.
There are two independent but similar approaches of replacing the official Tomcat JULI libraries by an SLF4J or Logback adapter: tomcat-slf4j and tomcat-slf-logback.
I've tried both, but in the end, I think it's easier to use nothing but the JUL-to-SLF4J bridge and other standard artifacts.