Liberate Your Components with OSGi Services

A presentation by Alasdair Nottingham, an IBM WAS developer describing their migration to OSGi. He described a Modularity Maturity Model covering the spectrum from no modularization through fully modularized. He described their upcoming Liberty profile as highly modular, after approximately 5-7 years work. It uses Declarative Services, Configuration Admin service, and Blueprint (Spring-based DI). He had a couple pointers for anyone making the same transition:

• Do not use a static class  to provide OSGi services. We've heard about this as an unattractive alternative to ServiceTracker use. He didn't describe what he thought should be used.
  
• An OSGi bundle is active when its activator#start returns - it may not yet have ready services.
• No service versioning yet.