○事象
Tomcat停止時、以下のようなメッセージが出力される
致命的: The web application [/appname] created a ThreadLocal with key of type [org.apache.log4j.helpers.ThreadLocalMap]
(value [org.apache.log4j.helpers.ThreadLocalMap@2b0e7ecc])
and a value of type [java.util.Hashtable] (value [{}]) but failed to remove it when the web application was stopped.
Threads are going to be renewed over time to try and avoid a probable memory leak.