Normally they contain no *.class files, but it is possible to precompile your JSPs, in which case they behave like Servlets. files.

The magic of *.war files is their completeness. All you need do is drop the *.war file in the run directory of any servlet womb, and that is all it needs to run the application. The womb can find out everything it needs to know primarily by examining the web.xml enclosed file. This works across platforms and across vendors. Sun nailed down the specifications of the *.war file in a platform-independent way. Its a bloody miracle, and something Sun deserves kudos for.

Here is what a simple war file looks like:

Here is what a simple web.xml file looks like: