Trait representing an object that can't be fully initialized by its
constructor. Useful for unifying the initialization process of an
HttpServlet and a Filter.
A hook to initialize the class with some configuration after it has
Not called init because GenericServlet doesn't override it, and then
we get into https://lampsvn.epfl.ch/trac/scala/ticket/2497.
A hook to shutdown the class.
A hook to shutdown the class. Bridges the gap between servlet's
destroy and filter's destroy.