There is too much code duplication between DefaultServlet and StandardContext to
look up static resource? I fail to understand why does DefaultServlet not use
ServletContext.getResource to serve the content? DefaultServlet has a hard
dependency on WebappClassLoader, which is really bad.
Because of code duplication, I also see that there are behavioral differences -
certain resources can be found by ServletContext, but they are never found by
DefaultServlet. e.g., ServletContext.getResources at the end calls
classLoader.getResource, but not check to see if the resource actually belonged
to WEB-INF/lib/*.jar not.