From Java Tips: Difference between ear jar and war files:
These files are simply zipped files
using the java jar tool. These files are
created for different purposes. Here
is the description of these files:
.jar files: The .jar files contain
libraries, resources and
accessories files like property files..war files: The war file contains
the web application that can be
deployed on any servlet/jsp
container. The .war file contains jsp,
html, javascript and other files
necessary for the development of web
applications.
Official Sun/Oracle descriptions:
- The J2EETM Tutorial: Web Application Archives
- The Java Archive (JAR) File Format: The Basics
Wikipedia articles:
- WAR file format (Sun)
- JAR file