Petals View

Every time we stop the tomcat, we've got this message:

GRAVE: The web application [/petals-view-ui] registered the JBDC 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.
1 oct. 2010 15:09:14 org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
GRAVE: The web application [/petals-view-ui] 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.
1 oct. 2010 15:09:14 org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
GRAVE: The web application [/petals-view-ui] appears to have started a thread named [H2 File Lock Watchdog /users/petalsgui/test/db/petalsview.lock.db] but has failed to stop it. This is very likely to create a memory leak.
1 oct. 2010 15:09:14 org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
GRAVE: The web application [/petals-view-ui] appears to have started a thread named [H2 Log Writer PETALSVIEW] but has failed to stop it. This is very likely to create a memory leak.

Is tomcat dummy? I don't think. So maybe there are some thread closings badly implemented...
Put this track as minor?