SEVERE warnings on context shutdown

hi while shutting down Tomcat I noticed the following statements in the logs:

Jan 14, 2013 12:16:24 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
SEVERE: The web application [/cms] registered the JDBC driver [org.h2.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
Jan 14, 2013 12:16:24 PM org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks
SEVERE: The web application [/cms] created a ThreadLocal with key of type [net.sf.json.AbstractJSON$1] (value [net.sf.json.AbstractJSON$1@3ebfbdd5]) and a value of type [java.util.HashSet] (value [[]]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
Jan 14, 2013 12:16:24 PM org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks
SEVERE: The web application [/cms] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@1e480b22]) and a value of type [org.apache.cxf.BusFactory.BusHolder] (value [org.apache.cxf.BusFactory$BusHolder@bd2f4b6]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.

SEVERE: The web application [/site] created a ThreadLocal with key of type [com.sun.xml.bind.v2.ClassFactory$1] (value [com.sun.xml.bind.v2.ClassFactory$1@7aa6c22a]) and a value of type [java.util.WeakHashMap] (value [

{class org.hippoecm.hst.site.addon.module.model.ModuleDefinition=java.lang.ref.WeakReference@5a15924e, class java.util.ArrayList=java.lang.ref.WeakReference@3e386d16}

]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
Jan 14, 2013 12:16:25 PM org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks
SEVERE: The web application [/site] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@6a81df43]) and a value of type [org.apache.cxf.BusFactory.BusHolder] (value [org.apache.cxf.BusFactory$BusHolder@7468de55]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
Jan 14, 2013 12:16:25 PM org.apache.coyote.http11.Http11Protocol destroy

Please note that, while they were caught during Tomcat Container shutdown, these errors would also occur during application hot redeploy.

Best,
Edoardo