Reduce errors logged when shutting down Confluence

Jul 12, 2011 10:37:59 AM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
SEVERE: The web application [/confluence] registered the JDBC driver [org.hsqldb.jdbc.JDBCDriver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
Jul 12, 2011 10:37:59 AM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
SEVERE: The web application [/confluence] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
Jul 12, 2011 10:37:59 AM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
SEVERE: The web application [/confluence] registered the JDBC 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.
2011-07-12 10:37:59,842 INFO [main] [com.atlassian.confluence.lifecycle] contextDestroyed Stopping Confluence
Jul 12, 2011 10:37:59 AM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/confluence] appears to have started a thread named [com.google.common.base.internal.Finalizer] but has failed to stop it. This is very likely to create a memory leak.
Jul 12, 2011 10:37:59 AM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: The web application [/confluence] created a ThreadLocal with key of type [com.atlassian.core.logging.ThreadLocalErrorCollection$2] (value [com.atlassian.core.logging.ThreadLocalErrorCollection$2@2dc4df0b]) and a value of type [java.lang.Boolean] (value [false]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
Jul 12, 2011 10:37:59 AM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: The web application [/confluence] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@580f62a6]) and a value of type [org.dom4j.DocumentFactory] (value [org.dom4j.DocumentFactory@5a15ad74]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
Jul 12, 2011 10:37:59 AM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: The web application [/confluence] created a ThreadLocal with key of type [com.atlassian.confluence.concurrent.ThreadLocalMap] (value [com.atlassian.confluence.concurrent.ThreadLocalMap@452ec8e0]) and a value of type [java.util.HashMap] (value [{}]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
log4j:ERROR LogMananger.repositorySelector was null likely due to error in class reloading, using NOPLoggerRepository.
Jul 12, 2011 10:38:00 AM org.apache.coyote.http11.Http11Protocol destroy
INFO: Stopping Coyote HTTP/1.1 on http-8080
Disconnected from server

Exception in thread "Timer-0" java.lang.NullPointerException
at com.mchange.v2.log.log4j.Log4jMLog$Log4jMLogger.isLoggable(Log4jMLog.java:257)
at com.mchange.v2.resourcepool.BasicResourcePool$CheckIdleResourcesTask.run(BasicResourcePool.java:1961)
at java.util.TimerThread.mainLoop(Unknown Source)
at java.util.TimerThread.run(Unknown Source)