这货倒底有啥用？
http://www.javaworld.com/javaworld/jw-03-2008/jw-03-osgi1.html?page=1 说：
1. You can install, uninstall, start, and stop different modules of your application dynamically without restarting the container.
2. Your application can have more than one version of a particular module running at the same time.
听起来有点像单JVM的SOA，对吧？