Versioning and common code-bases with Eclipse

I'd like to bring out an Android app in the near future, so I was wondering how to support a couple of funcitonalities I have got used whilst developing for J2ME and iPhone

• first the versioning. With J2ME (using NetBeans as IDE) I had the option to auto-increment the softwwares version every time I compiled it. I was wondering if something like this is available for Eclipse and if so how to use it ?
• secondly a common code base. Is it possible to have a common code base for several projects ? For exam开发者_JAVA技巧ple I might have a game which actually uses the same code but needs different graphic resources. I'd hate to have a different project for every game/app and have to manually edit every project's source every time I want to submit a new code-change. Any solution for this ?

Thanks in advance for every kind of help/hints/tips !

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Another idea:

If you can package the common code into Classes then a library approach would help. In eclipse under project properties you can add a library to your project.

Hope this helps you on.