title: 61 Duplicate classes in classes.jar, WHERE is classes.jar located?
body: <p>So, I have a noob problem with my app I've been working on for about two weeks. All of a sudden, it began to produce errors on launch!</p>
  
  <p>The app is almost done, and now it don't work anymore. The problem seem to be in classes.jar folder! And I can't find this folder, as the noob I am!</p>
  
  <p>I've tried pretty much all I've found on this thread, but nothing solves it...</p>
  
  <p>And i'm not even joking, I counted EACH ONE of those freaking errors.
  61 (YES) duplicates?! What the heck is going on..</p>
  
  <pre><code>Duplicate class com.google.android.gms.location.places.zza found in modules classes.jar (com.google.android.gms:play-services-places-placereport:16.0.0) and classes.jar (com.google.android.gms:play-services-places:9.6.1)
  Duplicate class com.google.android.gms.measurement.AppMeasurement found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zza found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzaa found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzab found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzac found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzad found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzae found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzaf found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzag found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzah found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzai found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzaj found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzak found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzal found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzb found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzc found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzd found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zze found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzf found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzg found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzh found in modules classes.jar (com.google.android.gms:play-services-measurement-sdk:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzi found in modules classes.jar (com.google.android.gms:play-services-measurement-sdk:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzj found in modules classes.jar (com.google.android.gms:play-services-measurement-sdk:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzk found in modules classes.jar (com.google.android.gms:play-services-measurement-sdk:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzl found in modules classes.jar (com.google.android.gms:play-services-measurement-sdk:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzm found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzn found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzo found in modules classes.jar (com.google.android.gms:play-services-measurement:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzp found in modules classes.jar (com.google.android.gms:play-services-measurement:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzq found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzr found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzs found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzt found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzu found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzv found in modules classes.jar (com.google.android.gms:play-services-measurement-impl:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzw found in modules classes.jar (com.google.android.gms:play-services-measurement:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzx found in modules classes.jar (com.google.android.gms:play-services-measurement:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzy found in modules classes.jar (com.google.android.gms:play-services-measurement:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.android.gms.measurement.internal.zzz found in modules classes.jar (com.google.android.gms:play-services-measurement:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.firebase.analytics.FirebaseAnalytics found in modules classes.jar (com.google.android.gms:play-services-measurement-api:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.firebase.analytics.FirebaseAnalytics$Event found in modules classes.jar (com.google.android.gms:play-services-measurement-api:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.firebase.analytics.FirebaseAnalytics$Param found in modules classes.jar (com.google.android.gms:play-services-measurement-api:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.firebase.analytics.FirebaseAnalytics$UserProperty found in modules classes.jar (com.google.android.gms:play-services-measurement-api:16.4.0) and classes.jar (com.google.firebase:firebase-analytics-impl:9.6.1)
  Duplicate class com.google.firebase.auth.AuthCredential found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.EmailAuthCredential found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.EmailAuthProvider found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.FacebookAuthCredential found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.FacebookAuthProvider found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.FirebaseAuthProvider found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.GithubAuthCredential found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.GithubAuthProvider found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.GoogleAuthCredential found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.GoogleAuthProvider found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.ProviderQueryResult found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.TwitterAuthCredential found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.TwitterAuthProvider found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.UserInfo found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.UserProfileChangeRequest found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.UserProfileChangeRequest$Builder found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  Duplicate class com.google.firebase.auth.zza found in modules classes.jar (com.google.firebase:firebase-auth-common:9.6.1) and classes.jar (com.google.firebase:firebase-auth:16.2.1)
  </code></pre>
  
  <p>I hope there's somebody out there that could help me with this. :)</p>