I have a webapp that uses Logback, deployed on a Tomcat instance. Upon shutdown, Tomcat reports this and doesn't completely shut down:

SEVERE: A web application created a ThreadLocal with key of type [org.slf4j.impl.CopyOnInheritThreadLocal] (value [org.slf4j.impl.CopyOnInheritThreadLocal@1bb35
b]) and a value of type [null] (value [null]) but failed to remove it when the web application was stopped. To prevent a memory leak, the ThreadLocal has been forcibly removed.
Feb 3, 2010 10:49:22 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: A web application created a ThreadLocal with key of type [null] (value [ch.qos.logback.core.UnsynchronizedAppenderBase$1@10e2558]) and a value of type [java.lang.Boolean] (value [false]) but failed to remove it when the web application was stopped. To prevent a memory leak, the ThreadLocal has been forcibly removed.

Is LogBack leaking resources?