Hibernate, as of 3.3, no longer distributes all jars needed to run the framework. SLF4J requires the inclusion of the SLF4J library as well as either a native or a wrapped implementation. The manual vaguely references such a need but it's never quite clear that the user must visit the SLF4J website and obtain these jars himself. Maven users are of course unaffected since the additional SLF4J jars are published in the central repo.
"Adapter" may be the wrong term here but I think the point has been made
Ok, this is really my last comment on this issue. Far too much time on it already...
Its not "a jar or two". I am not sure which all strictly constitute bindings but I see what appears to be 7, and that is not even accounting for dependencies of the bindings! For example, if we bundle slf4j-log4j12 by y'alls logic we also need to bundle some 1.2.x version of log4j, etc.
You are correct it was when you moved into a "consultant" role, not "contractor" role.
I reiterate my offer to default to an nop implementation in case no slf4j-binding could be found on the class path. It's a small change in the slf4j-api which would imo nicely address this issue. If interested, please open an slf4j bug report.