Android Build fail - java.lang.IllegalArgumentException: already added: Lcom/google/api/client/escape/CharEscapers;

Solution 1:

You have same jar library included twice. Check your application and all referenced Android libraries and make sure you have all jars included exactly once.

If that does not help, take a look at http://tools.android.com/knownissues. Specifically look at first issue described in Build System section.

Also you can read this post: How to fix the “Conversion to Dalvik format failed with error 1"

Solution 2:

I got this error after upgrading to R17.

My cause was different (ie not the *_src issue that occurred in R15). I had two different versions of a library in my "libs" folder. It appears that the Android plugin now automatically adds any jars in "libs" to the "Android Dependencies" section in the Package Explorer. Removing the old jar fixed the problem.