The whole OSGi movement is highly interesting. I recently investigated more into Component Orientation, reading an old book by Clemens Szyperski. Before I can understand SOA, first I must understand their basis: components. Feature driven approaches always deny the use of modularization. They argue that the cost to develop reusable components beat the long-term benefit of reuse. Therefore you should develop only the features you need in an agile manner, without caring for later reuse. That's great in the first iterations. Without de-composing your architecture the maintainance costs will explode in the following years. What you have to do is to plan your dependencies, your boundaries and gather similar functionalies at one place. So feature driven may turn out a legend. In the end you need to turn your code into components.

UPDATE: "the problem with java is that is has no modularity". Word! it-republik.de