Ah, to build, to build! That is the noblest art of all the arts. Painting and sculpture are but images, are merely shadows cast by outward things on stone or canvas, having in themselves no separate existence. Architecture, existing in itself, and not in seeming a something it is not, surpasses them as substance shadow.
—Henry Wadsworth Longfellow (1807–1882)

Technology does not drive change—it enables change.
—Unknown source

I started working with OSGi in about 2006. This was back in the days of BEA and WebLogic. Our goal was a very ambitious one: to create a new application server profiled for a particular vertical market—financial front offices.

The journey has been a long one. But as they say, it is not just about reaching the destination, but rather about the journey. I’ve learned more than I expected along the way. I’ve learned how to better develop reusable software, how to architect service-oriented implementations, and how to conceptualize software that is both maintainable and extensible.

The success of our project at BEA and now at Oracle is to a large extent a positive testimonial to the advantages of using OSGi. Relating my experience using OSGi and the advantages I’ve learned are the focus of this book.