Warnings when stopping Tomcat with Grouper deployed

Is there anything we can do about these warnings when stopping Tomcat (version 6.0.29) with grouper-ui and grouper-ws deployed?

Jun 27, 2011 2:11:02 PM org.apache.catalina.core.StandardService stop
INFO: Stopping service Catalina
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
SEVERE: The web application [/grouper-ws] registered the JBDC driver [oracle.jdbc.driver.OracleDriver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
SEVERE: The web application [/grouper-ws] registered the JBDC driver [org.postgresql.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
SEVERE: The web application [/grouper-ws] registered the JBDC driver [com.microsoft.sqlserver.jdbc.SQLServerDriver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/grouper-ws] appears to have started a thread named [Timer-4] but has failed to stop it. This is very likely to create a memory leak.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/grouper-ws] appears to have started a thread named [Timer-5] but has failed to stop it. This is very likely to create a memory leak.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/grouper-ws] appears to have started a thread named [Timer-7] but has failed to stop it. This is very likely to create a memory leak.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/grouper-ws] appears to have started a thread named com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0 but has failed to stop it. This is very likely to create a memory leak.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/grouper-ws] appears to have started a thread named com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1 but has failed to stop it. This is very likely to create a memory leak.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/grouper-ws] appears to have started a thread named com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2 but has failed to stop it. This is very likely to create a memory leak.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: The web application [/grouper-ws] created a ThreadLocal with key of type [org.apache.commons.lang.builder.ReflectionToStringBuilder$1] (value [org.apache.commons.lang.builder.ReflectionToStringBuilder$1@5a2045]) 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.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: The web application [/grouper-ws] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@fcabd6]) and a value of type [edu.internet2.middleware.grouper.hibernate.GrouperContext] (value [edu.internet2.middleware.grouper.hibernate.GrouperContext@758cdb]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: The web application [/grouper-ws] created a ThreadLocal with key of type [org.apache.commons.lang.builder.ReflectionToStringBuilder$1] (value [org.apache.commons.lang.builder.ReflectionToStringBuilder$1@5a2045]) 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.
Jun 27, 2011 2:11:06 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: The web application [/grouper-ws] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@fcabd6]) and a value of type [edu.internet2.middleware.grouper.hibernate.GrouperContext] (value [edu.internet2.middleware.grouper.hibernate.GrouperContext@1728f89]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.