Most people have been bit when trying to use Google's new Maps V2 API on Android because that functionality is now bundled/upgraded as part of their Play store. The symptom is when you're trying to use the library in your project in Eclipse, you click on ProjectProperties/Android/Library (don't use the Java Build Path) then add the project and it happily adds it with a green checkmark next to it:

However, if you go look at it again, that green checkmark becomes a red X and the reference is a full DOS path; if you look at your Java Build Path and the Android Private Libraries, you'll also notice the google-play-services_lib is also missing but the support library is there.

The workaround is during the project import of the Play Services library, make sure you click on the "Copy into workspace" checkbox:


If Play Services ever gets updated, you'll have to delete/import the library into your workspace again unless Google fixes this bug in the Eclipse ADT plugin. If you want this fixed, please star Android Issue 27199. It's been mentioned multiple times on StackOverflow also.