How can I solve this To prevent a memory leak the JDBC Driver has been forcibly unregistered

Question

When I am running my web application, I am getting a message. It runs fine but I get this message during shutdown.

SEVERE: A web application 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.

How can I handle this?

Answer 1

What can you do?

1. Ignore these warnings. Tomcat is doing its job right. The actual bug is in someone else's code (the JDBC driver in question), not in yours. Be happy that Tomcat did its job properly and wait until the JDBC driver vendor get it fixed so that you can upgrade the driver. 

2. On the other hand, you aren't supposed to drop a JDBC driver in webapp's /WEB-INF/lib, but only in server's /lib. If you still keep it in webapp's /WEB-INF/lib, then you should manually register and deregister it using a ServletContextListener.

3. Downgrade to Tomcat 6.0.23 or older so that you will not be bothered with those warnings. But it will silently keep leaking memory. Not sure if that's good to know after all. Those kind of memory leaks are one of the major causes behind OutofMemory issue during Tomcat hotdeployments.

4. Move the JDBC driver to Tomcat's /lib folder and have a connection pooled datasource to manage the driver.