What Is Spring?

When people ask me what Spring does, I have to stop and think about how to answer it in one sentence, which is not easy to do as you will see shortly. So, let me first start by quoting an excerpt directly out of the Spring Framework Reference Documentation (springframework.org) because it describes the framework well:

"...Spring provides a light-weight solution for building enterprise-ready applications, while still supporting the possibility of using declarative transaction management, remote access to your logic using RMI or web services, mailing facilities and various options in persisting your data to a database. Spring provides an MVC framework, transparent ways of integrating AOP into your software and a well-structured exception hierarchy including automatic mapping from proprietary exception hierarchies.

Spring could potentially be a one-stop shop for all your enterprise applications, however, Spring is modular, allowing you to use parts of it, without having to bring in the rest..."

Let's explore the "modular" aspect of Spring a bit further. Figure 6.1 (also taken directly out of the Spring Framework Reference Documentation) is probably the best way to get an immediate understanding of the various things Spring can do, and it shows precisely why it is difficult to describe the entire Spring Framework in a short sentence.

Figure 6.1. Overview of the Spring Framework (taken directly from the Spring Framework Reference Documentation found on springframework.org).

In this book, I use Spring Framework 2.0 RC1.