Book excerpt: Java EE developers increasingly want to utilize OSGi to develop modular applications for component and service-based architectures. But tools required for OSGi implementation have been slow to develop. Spring Dynamic Modules (Spring DM) is a framework that simplifies the creation of component and service-oriented architectures with OSGi, to build modular Java applications using the powerful Spring framework. Spring Dynamic Modules in Action presents the fundamental concepts of OSGi-basedapps and maps them to the familiar ideas of the Spring framework. Then, it teaches the techniques and concepts required to develop stable, flexible enterprise apps. Along the way, readers will learn to incorporate other topics including dependency injection and unit testing in an OSGi-based environment. Purchase of the print book comes with an offer of a free PDF, ePub, and Kindle eBook from Manning. Also available is all code from the book.