title: JDBC Driver has been forcibly unregistered by Tomcat 7, why?
body: <p>I have a problem in tomcat 7, and here are some info about it,</p>
  
  <p>1 - I have this message:</p>
  
  <pre><code>INFO: Reloading Context with name [/WebApp] has started
  Oct 04, 2013 12:20:50 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc
  SEVERE: The web application [/WebApp] 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.
  
  Oct 04, 2013 12:20:50 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
  SEVERE: The web application [/WebApp] appears to have started a thread named [Abandoned connection cleanup thread] but has failed to stop it. This is very likely to create a memory leak.
  Oct 04, 2013 12:20:51 PM org.apache.catalina.core.StandardContext reload
  INFO: Reloading Context with name [/WebApp] is completed
  </code></pre>
  
  <p>2 - When I reload the application the problem solved for about 20 hours then comes back again.</p>
  
  <p>3 - I have about 10 application deployed on the tomcat but just 2 of them gets this error.</p>
  
  <p>4 - the problem was not exist from the begging with these 2 apps but appeared from about 2 weeks.</p>
  
  <p>So how can I solve this and is it related to my code?</p>