In the past, I saw articles about OSGi passing in DZone's feeds, and never cared much about it. It's possible and desiderable to avoid contact with many technologies we are not considering for right now: somehow we have to limit the amount of new information in our self-improvement process to the actually useful fields.
However, the thesis subject (audio and video search) is interesting but it involves a large amount of Java technology, in particular a framework built on top of the OSGi model. Here comes the pain: I did not know what OSGi was at all. Instead of continue worrying about it, I decided to dive into OSGi and I'd like to recall my steps here so that you can decide to take a similar journey on an argument that you are required to know.
Step 1: Wikipedia
Wikipedia is the starting point of most of my researches, even if it is not 100% reliable as every community-crafted content is. Wikipedia took me from an empty word (OSGi) to a definition:
The OSGi framework is a module system and service platform for the Java programming language that implements a complete and dynamic component model, something that does not exist in standalone Java/VM environments.Moreover, well-written Wikipedia articles have many internal links to related material, both in the page body and in the See also section. Every new term you encounter usually points to its own definition, a scenery that can lead to a tab explosion but also to deep knowledge.
Step 2: define concepts in your own terms
I quickly discovered that OSGi applications are composed of bundles. The bundle term is part of the Ubiquitous Language of OSGi, but I did not know an exact definition. When you are doing a panoramic of a technology, it's useful to start with a good approximation which uses already grasped concepts:
OSGi bundles are particula JARs which includes some metadata files along with the hyerarchically organized .class files that contain the bytecode. Bundles export or import Java packages they respectively provide or require.This is an approximation, since JARs and bundles do not strictly overlap. But it is a good one and let me abstract away most of the bundle internal organization for a while.
Step 3: resources to learn more
- Google is often the best friend of a developer (as the GIYF acronym correctly says.) You can look for tutorials, but also for particular frequently asked questions.
- Books on the subject, particularly if they contain good code samples, are the best road to a deep understanding of the technology. However they may not be the right material if you're only looking for a crash course.
- YouTube videos are instead highly distilled knowledge, and the equivalent of a crash course. A 1-hour long talk can teach you very much about the assumptions and the usage of a framework like OSGi without effort: you just need to listen to the speaker.
- also a search on Wikimedia Commons will bring you a lot of diagrams about your preferred technology (example), used throughout all the Wikimedia Foundation wikis.
My first practising step was producing an OSGi bundle and deploying it in an OSGi framework. I've done it even before step 3 because I like to get a walking skeleton as soon as possible, but I've gone reviewing my code once I had learned a larger part of the theory. Getting a running example is always a confidence booster however, even if you are copying much of the code without knowing its meaning.
The same learning process is going on for me for other material I'm using in the thesis, such as BPEL and the SMILA framework. While there may be aliens with genetic memories, you shouldn't be afraid of new concepts: everything you know was learnt at some point in your life.