“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

Just for the other people who still have this problem and they have tried the above answers but still getting the error (which was my case), then my solution was to delete the project from Eclipse and re-import it again.

This made the Android library to be added again to my referenced libraries, so now I have two Android JAR files referenced, hence I deleted one of them and now it compiles fine.

Solution: Delete the project from Eclipse IDE and then re-import it again, then check for the above solutions.