Yesterday, I learned that OSGi Declarative Services (DS) and Blueprint Services (BS) are two different things. That was truly a D’Oh moment.
In DS, you create one component.xml file for each Service you want to share, which outlines the references to other services among other things. Overall this seems to be a nice alternative to writing bundle activators, but nothing earth shattering. On the bright side, DS is supported by Equinox for some time already, given you have the org.eclipse.equinox.ds bundle in your target platform.
Now with BS, things get more interesting. It’s basically the Spring way of doing things applied to the OSGi world. The XML configuration files of BS look very familiar when you have past experience with Spring-powered J2EE apps. You can define all the Services your bundle provides in one XML file, wire them up with other services and so on.