org.jboss.el.util.ReflectionUtil (from jboss-el) uses a
private static ReferenceCache methodCache
and this ReferenceCache is leaking a thread that is used for cleanup. You can't call a cleanup method from the outside.
Every redeployment of an application will leak one thread due to this bug. And it causes a memory leak as the web application class loader can't be unloaded due to this bug.
The pom.xml of jboss-el states "JBoss EL is a extended EL implementation, distributed with Seam", therefore I report this bug against Seam.
If this thread should really be necessary, it should have a proper name.