[logback-user] parameterized logging

One other question: String user = "chris"; log.debug("User {} is requesting system logs", user ); the log output I get is: User {} is requesting system logs So, clearly, parameterized logging is not working. I'm using logback classic 0.9.27 with slf4j api 1.6.1 and a bunch of other stuff to catch j.u.l and j.c.l. It looks like parameterized logging has been there for a long time though. It should be just that simple, shouldn't it?