A pattern describes a proven solution to a recurring design problem, placing particular emphasis on the context and forces surrounding the problem, and the consequences and impact of the solution.

This website provides a palette of patterns you can use in the context of designing Java 2 Platform, Enteprise Edition (J2EE) applications. Occasionally, new patterns will be added and new insights will be incorporated into the current patterns, so check back often for updates. The BluePrints patterns catalog is based around the Sun Java Center patterns catalog, described in the Core J2EE Patterns book by Deepak Alur, John Crupi, and Dan Malks. Core J2EE Patterns provides more detail on J2EE patterns and is an excellent resource in addition to this website. Each pattern in this website includes a brief description of the pattern itself, along with a reference to a more detailed pattern description, and provides examples that show how the pattern applies in a large J2EE application, the Java Pet Store sample application, version 1.3.1.

Why Use Patterns?

• They have been proven. Patterns reflect the experience, knowledge and insights of developers who have successfully used these patterns in their own work.

• They are reusable. Patterns provide a ready-made solution that can be adapted to different problems as necessary.

• They are expressive. Patterns provide a common vocabulary of solutions that can express large solutions succinctly.

It is important remember that patterns do not guarantee success. A pattern description indicates when the pattern may be applicable, but only experience can provide understanding of when a particular pattern will improve a design.

Where to Go from Here

Java BluePrints Patterns Catalog
This section contains the Java BluePrints catalog of recommended J2EE patterns. It includes code samples from the Java BluePrints reference applications such as the Java Pet Store sample application.

Core J2EE Patterns
This section contains the online version of the best-selling book on J2EE patterns from the Sun Java Center architects, Deepak Alur, John Crupi, and Dan Malks.

References and Resources
This section lists references which are cited throughout the J2EE pattern catalog.

J2EE Patterns Mailing List
We want your feedback! Join the j2eepatterns-interest mailing list to discuss J2EE patterns.