Android : How to add labels in gmail using Gmail API for android application

I'm beginner in android development, i trying to create a label in gmail using Gmail API services for android application with some reference. when i'm trying to add gmail service jar file its shows some error like below

[2014-08-01 03:12:20 - GoogleProfileDemo] Dx 1 error; aborting [2014-08-01 03:12:20 - GoogleProfileDemo] Conversion to Dalvik format failed with error 1

I cannot include this code to my app

GoogleCredential credential = new GoogleCredential()
        .setFromTokenResponse(response);

Please help... Thanks in advance