java.lang.IllegalAccessError: Class ref in pre-verified class resolved to unexpected implementation

Well that's a common error if u are messing around with google maps api.

go to Project > Properties > Java Build Path > Libraries and ensure that there is no android.jar or maps.jar directly included. You should only have Google Apis with at leastmaps.jar and android.jar as leaves.

As u can see in the image there are two maps.jar . You have to delete the first one and just leave the leaves of Google APIs