You'll never know what's behind a URL. An URL like http://www.somesite.com/news/topic/hi.jpg may cause the image to be generated dynamically, without there ever being a file called "hi.jpg" anywhere, or a directory named "news/topic".
I haven't said it in a long time, but: A file server is not a web server.
EVERY URL request that comes into a web application server is parsed by the framework, using the web.xml file for guidance. If the URL patterns in web.xml indicate that the URL addresses a servlet, that request will be passed to the indicated servlet. Otherwise, the application container will use the part of the URL that comes after the context but before the query as a path to a resource inside the WAR. And just as a reminder, a WAR isn't necessarily a set of files and directories. In its official form, it's a ZIP file containing a resource directory that can be - but doesn't have to be - exploded into a set of files and directories.
On the client side, there's no way to tell WHAT will be done to a URL inside the server. It may even end up rewritten. For example, in JSF, a "/admin/myPage.jsf" might end up pulling in an "/admin.xhtml" resource to actually build the response. Even a simple "/images/myPic.gif" could end up being rewritten to convert a JPEG resource located in a completely different directory tree into a returned GIF data stream.
An IDE is no substitute for an Intelligent Developer.
Bageshwar Pratap Narain
Joined: Mar 04, 2009
if they contain a last modified and created values,
you can re-request for the resource and check if http 304 is returned,
which means content not modified.