1. What Is Seam?

According to the official JBoss web site, JBoss Seam is a “lightweight framework for Java EE 5.0.” What does that mean? Isn’t Java EE (Enterprise Edition) 5.0 itself a collection of “frameworks”? Why do you need another one that is outside the official specification? Well, we view Seam as the “missing framework” that should have been included in Java EE 5.0. It sits on top of Java EE 5.0 frameworks to provide a consistent and easy-to-understand programming model for all components in an enterprise web application. It also makes stateful applications and business process-driven applications a breeze to develop. In other words, Seam is all about developer productivity and application scalability.

In this book, we show you how Seam can make development easier for you. We cover several web application examples to make our case. But before we get into concrete code examples, let’s first explain what exactly Seam does and introduce its key design principles. This will help you better understand how Seam works in applications throughout the book.