commons-lang has a potential memory leak

SEVERE: A web application created a ThreadLocal with key of type [org.apache.commons.lang.builder.ReflectionToStringBuilder$1] (value [org.apache.commons.lang.builder.ReflectionToStringBuilder$1@1b00a944]) and a value of type [java.util.HashSet] (value [[]]) but failed to remove it when the web application was stopped. To prevent a memory leak, the ThreadLocal has been forcibly removed.
May 27, 2016 2:36:49 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap

commons-lang was 2.1

parent pom version was 2.6