Unable to execute dex: Multiple dex files define

Unable to execute dex: Multiple dex files define Lyour_package
Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define


This case usually happened when You import same library twice. Delete ones, and everything will be ok.
Then, if You have libary, have class for example com.sample.MyClass.java
Then, at Your Project there is a class too at com.sample.MyClass.java. Then, this usually make crash.
So, rename your class or your package if this happened to You.