This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
The classpath for a web app is (at least)
plus all the JARs in the WEB-INF/lib/
In addition, servers may add further directories to the classpath to give access to shared resources between web apps and provid system / server resources.