I've got several Web apps running on a Tomcat 5.5 server, and I'm working on improving/updating the overall logging system used throughout the system. I already had some success with logback-classic. However, when I try to use logback-access (i.e. access the lbAccessStatus servlet), I get this exception: exception javax.servlet.ServletException: Wrapper cannot find servlet class ch.qos.logback.access.ViewStatusMessagesServlet or a class it depends on org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433) ... root cause java.lang.ClassNotFoundException: ch.qos.logback.access.ViewStatusMessagesServlet org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1386) ... I have everything set up according to the docs: common/lib: logback-classic-0.9.15.jar logback-core-0.9.15.jar server/lib: logback-access-0.9.15.jar Moving around the libraries doesn't seem to help. logback-classic seems to work fine, it's just logback-access that causes problems.