What's new with Mastering EJB 3.0:
More than 50% new and revised material
Four new chapters and one new appendix covering the latest features of the new release
Basic and advanced concepts (such as inheritance, relationships, and so on) of Java Persistence API defined entities
Information on integrating EJB applications with the outside world via the Java EE Connector technology
Tips and techniques for designing and deploying EJB for better performance
Best practices for EJB 3.0 application design, development and testing
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2. Version (Source) Control Tool
Originally posted by William Brogden:
For one thing, the HttpSessionBindingListener interface solves a problem related to the handling of user session invalidation. A session can become invalidated by:
1. The action of your servlet - when a user logs out
2. The action of the servlet container - at expiration of the timeout
If you have an object that has to do some "cleanup" before it is discarded, have it implement HttpSessionBindingListener.