Classloader leak!

Some interesting type of memory leak - classloader leak:
- Log4j primer
- IntrospectionUtils, DriverManager, DOM4J, Mozilla Rhino, etc
"...There are two main patterns that cause this situation. The first one is where a library loaded by the container has a cache that keeps strong references to objects or classes in the application. The second one is where the application has ThreadLocal data that is attached to a container thread. In tomcat this thread will be part of the thread pool, so it will never be garbage collected..."