Error :app:transformClassesWithJarMeringForDebug

[stigmat4j]

* What went wrong:
Execution failed for task ':app:transformClassesWithJarMergingForDebug'.
> com.android.build.transform.api.TransformException: java.util.zip.ZipException: duplicate entry: com/google/android/gms/measurement/internal/zzh.class

[hanweixing]

I met a problem about okhttp, and error tips are like yours. It might be a conflict between gcm and zzh.
I solved my problem like below:

you can have a try like my code, maybe solve your problem.