I had a look at the OSGi website and I'm still not understanding what it is all about?? Are they some kind of an authority that does the specifications for the Java based frameworks?? or is OSGi itself a framework like Spring? Also how important is OSGi in today"s Java market? If we take the current scenario, there is no more Sun Microsystems which means if OSGi sets the standards for the frameworks like the JCP, what would that mean to the vendors who make products and frameworks that adhere to these standards?
OSGi is the specification of a Java API; it is not an implementation (of which there several, most prominently Apache Felix and Eclipse Equinox). It's a niche technology, and a Java developer may well never have to deal with directly. Many developers will be using products that use OSGi internally, though, like the GlassFish app server and the Eclipse IDE. See the http://faq.javaranch.com/java/OSGiLinks page for a few good introductory articles.