Web Applications

A collection of servlets, JSPs, HTML documents, images, styles sheets, etc. is called a web application.
To simply deployment, they can be bundled into a web application archive (.war).

.war is just a .jar, with some extra structure:

index.html
picture.png
WEB-INF/web.xml
WEB-INF/lib/xerces.jar
WEB-INF/classes/HelloWorld.class