title: Duplicate class in classes.jar on build project after update of Android Studio
body: <p>I have recently update Android Studio to the latest version and since I have been facing problem with the libraries connecting to it. </p>
  
  <p>The latest problem faced is the following:</p>
  
  <p><a href="https://i.stack.imgur.com/08ElI.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/08ElI.jpg" alt="enter image description here"></a></p>
  
  <pre><code>Cause 1: java.util.concurrent.ExecutionException: java.lang.RuntimeException: Duplicate class     com.google.android.gms.internal.measurement.zzsr found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.internal.measurement.zzss found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.internal.measurement.zzst found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.internal.measurement.zzsu found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.internal.measurement.zzsv found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcu found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcv found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcw found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcx found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcy found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzdw found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  
  Go to the documentation to learn how to Fix dependency resolution errors.
  at java.util.concurrent.ForkJoinTask.get(ForkJoinTask.java:1006)
  at com.android.ide.common.workers.ExecutorServiceAdapter.await(ExecutorServiceAdapter.kt:56)
  at com.android.build.gradle.internal.tasks.CheckDuplicateClassesDelegate.run(CheckDuplicateClassesDelegate.kt:71)
  at com.android.build.gradle.internal.tasks.CheckDuplicateClassesTask.taskAction(CheckDuplicateClassesTask.kt:61)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:498)
  at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:103)
  at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:48)
  at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:41)
  at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:28)
  at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:702)
  at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:669)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$5.run(ExecuteActionsTaskExecuter.java:404)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:402)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:394)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:92)
  at org.gradle.internal.operations.DelegatingBuildOperationExecutor.run(DelegatingBuildOperationExecutor.java:31)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:393)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:376)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.access$200(ExecuteActionsTaskExecuter.java:80)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$TaskExecution.execute(ExecuteActionsTaskExecuter.java:213)
  at org.gradle.internal.execution.steps.ExecuteStep.lambda$execute$1(ExecuteStep.java:33)
  at java.util.Optional.orElseGet(Optional.java:267)
  at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:33)
  at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:26)
  at org.gradle.internal.execution.steps.CleanupOutputsStep.execute(CleanupOutputsStep.java:58)
  at org.gradle.internal.execution.steps.CleanupOutputsStep.execute(CleanupOutputsStep.java:35)
  at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:48)
  at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:33)
  at org.gradle.internal.execution.steps.CancelExecutionStep.execute(CancelExecutionStep.java:39)
  at org.gradle.internal.execution.steps.TimeoutStep.executeWithoutTimeout(TimeoutStep.java:73)
  at org.gradle.internal.execution.steps.TimeoutStep.execute(TimeoutStep.java:54)
  at org.gradle.internal.execution.steps.CatchExceptionStep.execute(CatchExceptionStep.java:35)
  at org.gradle.internal.execution.steps.CreateOutputsStep.execute(CreateOutputsStep.java:51)
  at org.gradle.internal.execution.steps.SnapshotOutputsStep.execute(SnapshotOutputsStep.java:45)
  at org.gradle.internal.execution.steps.SnapshotOutputsStep.execute(SnapshotOutputsStep.java:31)
  at org.gradle.internal.execution.steps.CacheStep.executeWithoutCache(CacheStep.java:201)
  at org.gradle.internal.execution.steps.CacheStep.execute(CacheStep.java:70)
  at org.gradle.internal.execution.steps.CacheStep.execute(CacheStep.java:45)
  at org.gradle.internal.execution.steps.BroadcastChangingOutputsStep.execute(BroadcastChangingOutputsStep.java:49)
  at org.gradle.internal.execution.steps.StoreSnapshotsStep.execute(StoreSnapshotsStep.java:43)
  at org.gradle.internal.execution.steps.StoreSnapshotsStep.execute(StoreSnapshotsStep.java:32)
  at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:38)
  at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:24)
  at org.gradle.internal.execution.steps.SkipUpToDateStep.executeBecause(SkipUpToDateStep.java:96)
  at org.gradle.internal.execution.steps.SkipUpToDateStep.lambda$execute$0(SkipUpToDateStep.java:89)
  at java.util.Optional.map(Optional.java:215)
  at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:54)
  at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:38)
  at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:77)
  at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:37)
  at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:36)
  at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:26)
  at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:90)
  at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:48)
  at org.gradle.internal.execution.impl.DefaultWorkExecutor.execute(DefaultWorkExecutor.java:33)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:120)
  at org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionStateTaskExecuter.execute(ResolveBeforeExecutionStateTaskExecuter.java:75)
  at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:62)
  at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:108)
  at org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionOutputsTaskExecuter.execute(ResolveBeforeExecutionOutputsTaskExecuter.java:67)
  at org.gradle.api.internal.tasks.execution.ResolveAfterPreviousExecutionStateTaskExecuter.execute(ResolveAfterPreviousExecutionStateTaskExecuter.java:46)
  at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:94)
  at org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute(FinalizePropertiesTaskExecuter.java:46)
  at org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute(ResolveTaskExecutionModeExecuter.java:95)
  at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:57)
  at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:56)
  at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:36)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.executeTask(EventFiringTaskExecuter.java:73)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:52)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:49)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:416)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:406)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:102)
  at org.gradle.internal.operations.DelegatingBuildOperationExecutor.call(DelegatingBuildOperationExecutor.java:36)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute(EventFiringTaskExecuter.java:49)
  at org.gradle.execution.plan.LocalTaskNodeExecutor.execute(LocalTaskNodeExecutor.java:43)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:355)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:343)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:336)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:322)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:134)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:129)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute(DefaultPlanExecutor.java:202)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.executeNextNode(DefaultPlanExecutor.java:193)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run(DefaultPlanExecutor.java:129)
  at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
  at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
  at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
  at java.lang.Thread.run(Thread.java:745)
  Caused by: java.lang.RuntimeException: Duplicate class com.google.android.gms.internal.measurement.zzsr found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.internal.measurement.zzss found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.internal.measurement.zzst found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.internal.measurement.zzsu found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.internal.measurement.zzsv found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcu found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcv found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcw found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcx found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzcy found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  Duplicate class com.google.android.gms.measurement.internal.zzdw found in modules classes.jar (com.google.android.gms:play-services-measurement-base:16.3.0) and classes.jar (com.google.firebase:firebase-analytics-impl:16.2.1)
  
  Go to the documentation to learn how to Fix dependency resolution errors.
  at com.android.build.gradle.internal.tasks.CheckDuplicatesRunnable.run(CheckDuplicateClassesDelegate.kt:132)
  at com.android.ide.common.workers.ExecutorServiceAdapter$submit$submission$1.run(ExecutorServiceAdapter.kt:40)
  at java.util.concurrent.ForkJoinTask$AdaptedRunnableAction.exec(ForkJoinTask.java:1386)
  at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
  at java.util.concurrent.ForkJoinTask.externalInterruptibleAwaitDone(ForkJoinTask.java:361)
  at java.util.concurrent.ForkJoinTask.get(ForkJoinTask.java:1001)
  ... 99 more
  </code></pre>
  
  <p>Find below the <strong>app Gradle</strong>:</p>
  
  <pre><code>apply plugin: 'com.android.application'
  apply plugin: 'io.fabric'
  
  
  android {
      compileSdkVersion 28
      buildToolsVersion '28.0.3'
      useLibrary  'org.apache.http.legacy'
  
      defaultConfig {
          applicationId "com.packageName"
          minSdkVersion 24
          targetSdkVersion 28
          multiDexEnabled true
      }
  
      buildTypes {
          release {
              minifyEnabled true
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-project.txt'
          }
      }
  
      lintOptions {
          disable "ResourceType"
      }
  }
  
  ext {
      googlePlayServicesVersion = "4.2.0"
  }
  
  
  dependencies {
      implementation files('libs/icu4j-4_4_2_2.jar')
      implementation files('libs/jsoup-1.6.3.jar')
      implementation files('libs/ksoap2-android-assembly-2.6.0-jar-with-dependencies.jar')
      implementation files('libs/zip4j_1.2.6.jar')
  
      implementation('com.crashlytics.sdk.android:crashlytics:2.9.9@aar')     {
          transitive = true;
      }
  
      implementation 'com.facebook.android:facebook-android-sdk:4.38.1'
      implementation 'com.google.android.gms:play-services-auth:16.0.1'
      implementation'com.google.firebase:firebase-auth:16.1.0'
  
      // Firebase
      implementation 'com.google.firebase:firebase-messaging:17.3.4'
      implementation 'com.google.firebase:firebase-core:16.0.3'
  
      implementation 'com.google.android.gms:play-services-ads:17.2.1'
  
      implementation project(':pdflibrary')
      implementation 'com.android.support:support-compat:28.0.0'
      implementation 'com.android.support:cardview-v7:28.0.0'
      implementation 'com.android.support:customtabs:28.0.0'
      implementation'junit:junit:4.12'
  
      implementation 'com.android.support:appcompat-v7:28.0.0'
      implementation 'com.android.support:recyclerview-v7:28.0.0'
  
      implementation 'com.google.android.gms:play-services-flags:16.0.1'   
  }
  </code></pre>
  
  <p>Find below the <strong>pdf Library Gradle</strong>:</p>
  
  <pre><code>apply plugin: 'com.android.library'
  
  android {
      compileSdkVersion 28
      buildToolsVersion '28.0.3'
  
      defaultConfig {
          minSdkVersion 24
          targetSdkVersion 28
          versionCode 1
          versionName '1'
      }
  
      sourceSets {
          main {
              jniLibs.srcDirs = ['libs']
          }
      }
  }
  
  dependencies {
      implementation fileTree(include: ['*.jar'], dir: 'libs')
  }
  </code></pre>
  
  <p>Find below the <strong>Project Gradle</strong>:</p>
  
  <pre><code>buildscript {
      repositories {
          mavenCentral()
          maven { url 'https://maven.fabric.io/public' }
          google()
  
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:3.4.1'
          classpath 'io.fabric.tools:gradle:1.29.0'
          classpath 'com.google.gms:google-services:4.1.0'
      }
  
  }
  
  allprojects {
      repositories {
          mavenCentral()
          google()
          maven { url 'https://maven.fabric.io/public' }
          jcenter()
      }
  }
  </code></pre>
  
  <p>I have checked the following questions but no suggestion would work: 
  <a href="https://stackoverflow.com/questions/36990054/android-studio-resolving-duplicate-classes">Android Studio: Resolving Duplicate Classes</a></p>
  
  <p>This could be a duplicate question of the following:
  <a href="https://stackoverflow.com/questions/55977552/61-duplicate-classes-in-classes-jar-where-is-classes-jar-located">61 Duplicate classes in classes.jar, WHERE is classes.jar located?</a>. But unfortunately it was not answered. I hope it would attract attention to the issue.</p>