How it could be happen that "org.eclipse.core.runtime" is needed in MANIFEST.MF?

I've created simple "plug-in" project. But when I tried to create plug-in class which extends "org.eclipse.core.runtime.Plugin" it said that the name couldn't be resolved. I've added "org.eclipse.core.runtime" to Require-Bundle,

but wondering how it could be that I HAVE to add it to Require-Bundle?

Isn't it s开发者_如何转开发hould be loaded irrelevant to MANIFEST.MF? Or is it a new feature of Eclipse?

In OSGi you have to declare dependency on every bundle or package you consume. The only thing that's directly accessible are basic JRE classes and OSGi API itself.