“Conversion to Dalvik format failed with error 1” on external JAR

Question

In my Android application in Eclipse I get the following error.

UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.IllegalArgumentException: already add

Answer 1

My problem was caused by ADT version 12.0 and ProGuard integration. This bug is well documented and the solution is in the documentation

Solution is in here

ProGuard command line