title: Tomcat 6 memory leaks log entries
body: <p>Below is outtake of unique entries in my Catalina.out file on CentOS machine. I'm running Tomcat 6 with spring 3 and my application. There is whole bunch of them so I just picked some that keep repeating. This doesn't happen all the time but it happens at least once a week.</p>
  <h2>The Question is what can I do to prevent the bellow from happening?</h2>
  <pre><code>Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
  
  SEVERE: The web application [] registered the JBDC 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.
  
  Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
  
  SEVERE: The web application [] appears to have started a thread named [com.iteezy.shared.domain.DirEntry.data] but has failed to stop it. This is very likely to create a memory leak.
  
  
  Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
  SEVERE: The web application [] 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.
  
  
  Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads  
  
  SEVERE: The web application [] appears to have started a thread named [File Reaper] but has failed to stop it. This is very likely to create a memory leak.
  
  Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
  
  SEVERE: The web application [] appears to have started a thread named [pool-1-thread-22] but has failed to stop it. This is very likely to create a memory leak.  
  
  37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
  b application [] appears to have started a thread named 
  
  [org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-2] but has failed to stop it. This is very likely to create a memory leak.
  
  37:48 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
  
  b application [] created a ThreadLocal with key of type [net.sf.json.AbstractJSON$1] (value [net.sf.json.AbstractJSON$1@40bbb3d6]) 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.
  </code></pre>