title: DuplicateFileException error while building Android APK
body: <p>I am using Android Studio 2.0 on Windows 7. When building my Android project, I get the following error:</p>
  
  <pre><code>:app:transformResourcesWithMergeJavaResForDebug FAILED
  
  FAILURE: Build failed with an exception.
  
  * What went wrong:
  Execution failed for task ':app:transformResourcesWithMergeJavaResForDebug'.
  &gt; com.android.build.api.transform.TransformException: com.android.builder.packaging.DuplicateFileException: Duplicate files copied in APK com/google/appengine/repackaged/org/apache/commons/codec/language/bm/sep_approx_spanish.txt
  File1: C:\Users\USER\.gradle\caches\modules-2\files-2.1\com.google.appengine\appengine-api-1.0-sdk\1.9.28\e92c18272b555027d9ec666e7a89162f10638314\appengine-api-1.0-sdk-1.9.28.jar
  File2: C:\Users\USER\.gradle\caches\modules-2\files-2.1\com.google.appengine\appengine-endpoints\1.9.28\bf2e8a74bd28e388b3487fc78a0c7adfa592fd5d\appengine-endpoints-1.9.28.jar`
  </code></pre>
  
  <p>I have been digging around for hours and can't see anything that causes this. I've deleted .gradle in my home directory, but it just rebuilds it all the same. Does anyone know what causes this?</p>
  
  <p>Full gradle output:</p>
  
  <pre><code>Executing tasks: [:app:clean, :app:generateDebugSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies, :app:generateDebugAndroidTestSources, :app:assembleDebug]
  
  Configuration on demand is an incubating feature.
  WARNING: Dependency org.apache.httpcomponents:httpclient:4.0.1 is ignored for debug as it may be conflicting with the internal version provided by Android.
       In case of problem, please repackage it with jarjar to change the class packages
  WARNING: Dependency org.apache.httpcomponents:httpclient:4.0.1 is ignored for release as it may be conflicting with the internal version provided by Android.
       In case of problem, please repackage it with jarjar to change the class packages
  Incremental java compilation is an incubating feature.
  :app:clean
  :app:preBuild UP-TO-DATE
  :app:preDebugBuild UP-TO-DATE
  :app:checkDebugManifest
  :app:preReleaseBuild UP-TO-DATE
  :backend:appengineDownloadSdk
  :backend:compileJava
  :backend:processResources UP-TO-DATE
  :backend:classes
  :backend:appengineEndpointsGetClientLibs UP-TO-DATE
  :backend:appengineEndpointsExpandClientLibs UP-TO-DATE
  :backend:compileEndpointsSrcJava
  :backend:processEndpointsSrcResources UP-TO-DATE
  :backend:endpointsSrcClasses
  :backend:_appengineEndpointsAndroidArtifact UP-TO-DATE
  :backend:jar UP-TO-DATE
  :app:prepareComAndroidSupportAnimatedVectorDrawable2330Library
  :app:prepareComAndroidSupportAppcompatV72330Library
  :app:prepareComAndroidSupportSupportV42330Library
  :app:prepareComAndroidSupportSupportVectorDrawable2330Library
  :app:prepareComGoogleAndroidGmsPlayServicesAuth840Library
  :app:prepareComGoogleAndroidGmsPlayServicesBase840Library
  :app:prepareComGoogleAndroidGmsPlayServicesBasement840Library
  :app:prepareComGoogleAndroidGmsPlayServicesMeasurement840Library
  :app:prepareDebugDependencies
  :app:compileDebugAidl
  :app:compileDebugRenderscript
  :app:generateDebugBuildConfig
  :app:generateDebugAssets UP-TO-DATE
  :app:mergeDebugAssets
  :app:generateDebugResValues UP-TO-DATE
  :app:processDebugGoogleServices
  :app:generateDebugResources
  :app:mergeDebugResources
  :app:processDebugManifest
  :app:processDebugResources
  :app:generateDebugSources
  :app:mockableAndroidJar UP-TO-DATE
  :app:preDebugUnitTestBuild UP-TO-DATE
  :app:prepareDebugUnitTestDependencies
  :app:preDebugAndroidTestBuild UP-TO-DATE
  :app:prepareDebugAndroidTestDependencies
  :app:compileDebugAndroidTestAidl
  :app:processDebugAndroidTestManifest
  :app:compileDebugAndroidTestRenderscript
  :app:generateDebugAndroidTestBuildConfig
  :app:generateDebugAndroidTestAssets UP-TO-DATE
  :app:mergeDebugAndroidTestAssets
  :app:generateDebugAndroidTestResValues UP-TO-DATE
  :app:generateDebugAndroidTestResources
  :app:mergeDebugAndroidTestResources
  :app:processDebugAndroidTestResources
  :app:generateDebugAndroidTestSources
  :app:compileDebugJavaWithJavac
  Note: Some input files use unchecked or unsafe operations.
  Note: Recompile with -Xlint:unchecked for details.
  
  :app:compileDebugNdk UP-TO-DATE
  :app:compileDebugSources
  :app:buildInfoDebugLoader
  :app:transformClassesWithExtractJarsForDebug
  :app:transformClassesWithInstantRunVerifierForDebug
  :app:transformClassesWithJavaResourcesVerifierForDebug UP-TO-DATE
  :app:mergeDebugJniLibFolders
  :app:transformNative_libsWithMergeJniLibsForDebug
  :app:processDebugJavaRes UP-TO-DATE
  :app:transformResourcesWithMergeJavaResForDebug FAILED
  
  FAILURE: Build failed with an exception.
  
  * What went wrong:
  Execution failed for task ':app:transformResourcesWithMergeJavaResForDebug'.
  &gt; com.android.build.api.transform.TransformException:     com.android.builder.packaging.DuplicateFileException: Duplicate files copied in APK com/google/appengine/repackaged/org/apache/commons/codec/language/bm/sep_approx_spanish.txt
  File1: C:\Users\USER\.gradle\caches\modules-2\files-2.1\com.google.appengine\appengine-api-1.0-sdk\1.9.28\e92c18272b555027d9ec666e7a89162f10638314\appengine-api-1.0-sdk-1.9.28.jar
  File2: C:\Users\USER\.gradle\caches\modules-2\files-2.1\com.google.appengine\appengine-endpoints\1.9.28\bf2e8a74bd28e388b3487fc78a0c7adfa592fd5d\appengine-endpoints-1.9.28.jar
  
  
  * Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
  
  BUILD FAILED
  
  Total time: 15.364 secs
  </code></pre>
  
  <p>From what I can tell, it's a conflict between two dependencies:</p>
  
  <pre><code>dependencies {
    appengineSdk 'com.google.appengine:appengine-java-sdk:1.9.28'
    compile 'com.google.appengine:appengine-endpoints:1.9.28'
    compile 'com.google.appengine:appengine-endpoints-deps:1.9.28'
    compile 'javax.servlet:servlet-api:2.5'
    compile 'com.google.http-client:google-http-client-jackson2:1.20.0'
    compile 'com.google.http-client:google-http-client-gson:1.19.0'
  }
  </code></pre>
  
  <p>I think it's these two dependencies:</p>
  
  <pre><code>appengineSdk 'com.google.appengine:appengine-java-sdk:1.9.28'
  compile 'com.google.appengine:appengine-endpoints:1.9.28'
  compile 'com.google.appengine:appengine-endpoints-deps:1.9.28'
  </code></pre>
  
  <p>I'm not able to remove any of these, as it causes compile errors on the backend module. It looks like those two dependencies are almost identical, however. Should they both be in there? Any advice is appreciated!</p>