“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

I ran into this problem but my solution was twofold. 1.) I had to add an Android target version under project -> properties -> Android. 2.) I didn't have all google 'third party add-ons'. Click in AVD SDK manager under available packages -> third-party add-ons -> Google Inc. I downloaded all of the SDKs and that solved my issue.