json-lib is abandoned, might have threadlocal memory problems

from tomcat 6.0.26

May 27, 2016 5:01:13 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: A web application created a ThreadLocal with key of type [net.sf.json.AbstractJSON.CycleSet] (value [net.sf.json.AbstractJSON$CycleSet@9b6dce3]) and a value of type [java.lang.ref.SoftReference] (value [java.lang.ref.SoftReference@445fc010]) but failed to remove it when the web application was stopped. To prevent a memory leak, the ThreadLocal has been forcibly removed.