OSGi is a tried and true modularity standard for Java. It has in recent years gained a lot of traction and tooling; becoming frequently used in Enterprise containers and distributed software systems.
"Instant OSGi Starter" is where you should start before beginning your first OSGi based project. You’ll be exposed to the core concepts, gain practical experience with the most important features, and learn about the basic tenets of modular code practices.
This book begins with the fundamental tools needed for building modular applications, top features with basic tenets of modular core practices and provides useful insights into resources and the community.
As this book progresses you will be able to get started programming in OSGi whilst looking at the default three layer design so the application will be architected towards modularity and simplicity.
Through exploring several tools and technologies and browsing the communities you will be able to work towards modular programming in OSGi.