“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

In my case the problem is actually with OpenFeint API project. I have added OpenFeint as library project:

.

It is also added into build path, ADT tools 16 gives error with this sceneario.

Right click on your project and click build path, configure the build path and then see the image and remove your project OpenFeint from here and all is done :)