title: Android Studio Gradle Release Build Fails - With Minify Option
body: <p>I recently tried to build one of my Android Studio projects in release mode. I turned minifying on and also used a valid and working keystore for my build. </p>
  
  <p>Now when Gradle tried to build my project it didn't had any warnings, but failed once it tried to compute hashes out of my <code>classes.jar</code>. Since I had no error at all I built it again with the --stacktrace option. This is the gradle console output I got:</p>
  
  <pre><code>Executing tasks: [:app:assembleRelease]
  
  The client will now receive all logging from the daemon (pid: 7400). The daemon log file: C:\Users\J\.gradle\daemon\2.4\daemon-7400.out.log
  Starting 31st build in daemon [uptime: 52 mins 6.04 secs, performance: 97%, memory: 30% of 954,7 MB]
  Executing build with daemon context: DefaultDaemonContext[uid=07be96dd-38be-4476-92f7-915ae0599018,javaHome=C:\Program Files\Java\jdk1.8.0_11,daemonRegistryDir=C:\Users\J\.gradle\daemon,pid=7400,idleTimeout=10800000,daemonOpts=-XX:MaxPermSize=256m,-XX:+HeapDumpOnOutOfMemoryError,-Xmx1024m,-Dfile.encoding=windows-1252,-Duser.country=DE,-Duser.language=de,-Duser.variant]
  Closing daemon's stdin at end of input.
  The daemon will no longer process any standard input.
  Starting Build
  Settings evaluated using settings file 'C:\Users\J\AndroidStudioProjects\A\settings.gradle'.
  Projects loaded. Root project using build file 'C:\Users\J\AndroidStudioProjects\A\build.gradle'.
  Included projects: [root project 'A', project ':app']
  Configuration on demand is an incubating feature.
  Evaluating root project 'A' using build file 'C:\Users\J\AndroidStudioProjects\A\build.gradle'.
  Evaluating project ':app' using build file 'C:\Users\J\AndroidStudioProjects\A\app\build.gradle'.
  Creating configuration compile.
  Creating configuration apk.
  Creating configuration provided.
  Creating configuration wearApp.
  Creating configuration androidTestCompile.
  Creating configuration androidTestApk.
  Creating configuration androidTestProvided.
  Creating configuration androidTestWearApp.
  Creating configuration testCompile.
  Creating configuration testApk.
  Creating configuration testProvided.
  Creating configuration testWearApp.
  Creating configuration debugCompile.
  Creating configuration debugApk.
  Creating configuration debugProvided.
  Creating configuration debugWearApp.
  Creating configuration testDebugCompile.
  Creating configuration testDebugApk.
  Creating configuration testDebugProvided.
  Creating configuration testDebugWearApp.
  Creating configuration releaseCompile.
  Creating configuration releaseApk.
  Creating configuration releaseProvided.
  Creating configuration releaseWearApp.
  Creating configuration testReleaseCompile.
  Creating configuration testReleaseApk.
  Creating configuration testReleaseProvided.
  Creating configuration testReleaseWearApp.
  Selected primary task ':app:assembleRelease' from project :app
  All projects evaluated.
  Tasks to be executed: [task ':app:preBuild', task ':app:preReleaseBuild', task ':app:checkReleaseManifest', task ':app:preDebugBuild', task ':app:prepareComAndroidSupportAppcompatV72310Library', task ':app:prepareComAndroidSupportPaletteV72301Library', task ':app:prepareComAndroidSupportRecyclerviewV72301Library', task ':app:prepareComAndroidSupportSupportV42310Library', task ':app:prepareComGithubSiyamedAndroidShapeImageview093Library', task ':app:prepareComJjoe64Graphview401Library', task ':app:prepareComSothreeSlidinguppanelLibrary311Library', task ':app:prepareComTonicartosSuperslim0413Library', task ':app:prepareReleaseDependencies', task ':app:compileReleaseAidl', task ':app:compileReleaseRenderscript', task ':app:generateReleaseBuildConfig', task ':app:generateReleaseAssets', task ':app:mergeReleaseAssets', task ':app:generateReleaseResValues', task ':app:generateReleaseResources', task ':app:mergeReleaseResources', task ':app:processReleaseManifest', task ':app:processReleaseResources', task ':app:generateReleaseSources', task ':app:processReleaseJavaRes', task ':app:compileReleaseJavaWithJavac', task ':app:compileReleaseNdk', task ':app:compileReleaseSources', task ':app:proguardRelease', task ':app:dexRelease', task ':app:validateExternalOverrideSigning', task ':app:packageRelease', task ':app:zipalignRelease', task ':app:assembleRelease']
  :app:preBuild (Thread[Daemon worker Thread 11,5,main]) started.
  :app:preBuild
  In-memory cache of C:\Users\J\AndroidStudioProjects\A\.gradle\2.4\taskArtifacts\fileHashes.bin: Size{2725}, CacheStats{hitCount=0, missCount=0, loadSuccessCount=0, loadExceptionCount=0, totalLoadTime=0, evictionCount=0}
  In-memory cache of C:\Users\J\AndroidStudioProjects\A\.gradle\2.4\taskArtifacts\outputFileStates.bin: Size{70}, CacheStats{hitCount=0, missCount=0, loadSuccessCount=0, loadExceptionCount=0, totalLoadTime=0, evictionCount=0}
  In-memory cache of C:\Users\J\AndroidStudioProjects\A\.gradle\2.4\taskArtifacts\fileSnapshots.bin: Size{338}, CacheStats{hitCount=0, missCount=0, loadSuccessCount=0, loadExceptionCount=0, totalLoadTime=0, evictionCount=0}
  In-memory cache of C:\Users\J\AndroidStudioProjects\A\.gradle\2.4\taskArtifacts\taskArtifacts.bin: Size{42}, CacheStats{hitCount=0, missCount=0, loadSuccessCount=0, loadExceptionCount=0, totalLoadTime=0, evictionCount=0}
  Skipping task ':app:preBuild' as it has no actions.
  :app:preBuild UP-TO-DATE
  :app:preBuild (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.004 secs.
  :app:preReleaseBuild (Thread[Daemon worker Thread 11,5,main]) started.
  :app:preReleaseBuild
  Skipping task ':app:preReleaseBuild' as it has no actions.
  :app:preReleaseBuild UP-TO-DATE
  :app:preReleaseBuild (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:checkReleaseManifest (Thread[Daemon worker Thread 11,5,main]) started.
  :app:checkReleaseManifest
  Executing task ':app:checkReleaseManifest' (up-to-date check took 0.0 secs) due to:
    Task has not declared any outputs.
  :app:checkReleaseManifest (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.002 secs.
  :app:preDebugBuild (Thread[Daemon worker Thread 11,5,main]) started.
  :app:preDebugBuild
  Skipping task ':app:preDebugBuild' as it has no actions.
  :app:preDebugBuild UP-TO-DATE
  :app:preDebugBuild (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.0 secs.
  :app:prepareComAndroidSupportAppcompatV72310Library (Thread[Daemon worker Thread 11,5,main]) started.
  :app:prepareComAndroidSupportAppcompatV72310Library
  Skipping task ':app:prepareComAndroidSupportAppcompatV72310Library' as it is up-to-date (took 0.052 secs).
  :app:prepareComAndroidSupportAppcompatV72310Library UP-TO-DATE
  :app:prepareComAndroidSupportAppcompatV72310Library (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.053 secs.
  :app:prepareComAndroidSupportPaletteV72301Library (Thread[Daemon worker Thread 11,5,main]) started.
  :app:prepareComAndroidSupportPaletteV72301Library
  Skipping task ':app:prepareComAndroidSupportPaletteV72301Library' as it is up-to-date (took 0.001 secs).
  :app:prepareComAndroidSupportPaletteV72301Library UP-TO-DATE
  :app:prepareComAndroidSupportPaletteV72301Library (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:prepareComAndroidSupportRecyclerviewV72301Library (Thread[Daemon worker Thread 11,5,main]) started.
  :app:prepareComAndroidSupportRecyclerviewV72301Library
  Skipping task ':app:prepareComAndroidSupportRecyclerviewV72301Library' as it is up-to-date (took 0.001 secs).
  :app:prepareComAndroidSupportRecyclerviewV72301Library UP-TO-DATE
  :app:prepareComAndroidSupportRecyclerviewV72301Library (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:prepareComAndroidSupportSupportV42310Library (Thread[Daemon worker Thread 11,5,main]) started.
  :app:prepareComAndroidSupportSupportV42310Library
  Skipping task ':app:prepareComAndroidSupportSupportV42310Library' as it is up-to-date (took 0.002 secs).
  :app:prepareComAndroidSupportSupportV42310Library UP-TO-DATE
  :app:prepareComAndroidSupportSupportV42310Library (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.003 secs.
  :app:prepareComGithubSiyamedAndroidShapeImageview093Library (Thread[Daemon worker Thread 11,5,main]) started.
  :app:prepareComGithubSiyamedAndroidShapeImageview093Library
  Skipping task ':app:prepareComGithubSiyamedAndroidShapeImageview093Library' as it is up-to-date (took 0.002 secs).
  :app:prepareComGithubSiyamedAndroidShapeImageview093Library UP-TO-DATE
  :app:prepareComGithubSiyamedAndroidShapeImageview093Library (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.002 secs.
  :app:prepareComJjoe64Graphview401Library (Thread[Daemon worker Thread 11,5,main]) started.
  :app:prepareComJjoe64Graphview401Library
  Skipping task ':app:prepareComJjoe64Graphview401Library' as it is up-to-date (took 0.001 secs).
  :app:prepareComJjoe64Graphview401Library UP-TO-DATE
  :app:prepareComJjoe64Graphview401Library (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.002 secs.
  :app:prepareComSothreeSlidinguppanelLibrary311Library (Thread[Daemon worker Thread 11,5,main]) started.
  :app:prepareComSothreeSlidinguppanelLibrary311Library
  Skipping task ':app:prepareComSothreeSlidinguppanelLibrary311Library' as it is up-to-date (took 0.001 secs).
  :app:prepareComSothreeSlidinguppanelLibrary311Library UP-TO-DATE
  :app:prepareComSothreeSlidinguppanelLibrary311Library (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:prepareComTonicartosSuperslim0413Library (Thread[Daemon worker Thread 11,5,main]) started.
  :app:prepareComTonicartosSuperslim0413Library
  Skipping task ':app:prepareComTonicartosSuperslim0413Library' as it is up-to-date (took 0.001 secs).
  :app:prepareComTonicartosSuperslim0413Library UP-TO-DATE
  :app:prepareComTonicartosSuperslim0413Library (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:prepareReleaseDependencies (Thread[Daemon worker Thread 11,5,main]) started.
  :app:prepareReleaseDependencies
  Executing task ':app:prepareReleaseDependencies' (up-to-date check took 0.0 secs) due to:
    Task has not declared any outputs.
  :app:prepareReleaseDependencies (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:compileReleaseAidl (Thread[Daemon worker Thread 11,5,main]) started.
  :app:compileReleaseAidl
  Skipping task ':app:compileReleaseAidl' as it is up-to-date (took 0.004 secs).
  :app:compileReleaseAidl UP-TO-DATE
  :app:compileReleaseAidl (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.006 secs.
  :app:compileReleaseRenderscript (Thread[Daemon worker Thread 11,5,main]) started.
  :app:compileReleaseRenderscript
  Skipping task ':app:compileReleaseRenderscript' as it is up-to-date (took 0.007 secs).
  :app:compileReleaseRenderscript UP-TO-DATE
  :app:compileReleaseRenderscript (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.009 secs.
  :app:generateReleaseBuildConfig (Thread[Daemon worker Thread 11,5,main]) started.
  :app:generateReleaseBuildConfig
  Skipping task ':app:generateReleaseBuildConfig' as it is up-to-date (took 0.001 secs).
  :app:generateReleaseBuildConfig UP-TO-DATE
  :app:generateReleaseBuildConfig (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.002 secs.
  :app:generateReleaseAssets (Thread[Daemon worker Thread 11,5,main]) started.
  :app:generateReleaseAssets
  Skipping task ':app:generateReleaseAssets' as it has no actions.
  :app:generateReleaseAssets UP-TO-DATE
  :app:generateReleaseAssets (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:mergeReleaseAssets (Thread[Daemon worker Thread 11,5,main]) started.
  :app:mergeReleaseAssets
  Skipping task ':app:mergeReleaseAssets' as it is up-to-date (took 0.004 secs).
  :app:mergeReleaseAssets UP-TO-DATE
  :app:mergeReleaseAssets (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.005 secs.
  :app:generateReleaseResValues (Thread[Daemon worker Thread 11,5,main]) started.
  :app:generateReleaseResValues
  Skipping task ':app:generateReleaseResValues' as it is up-to-date (took 0.001 secs).
  :app:generateReleaseResValues UP-TO-DATE
  :app:generateReleaseResValues (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.002 secs.
  :app:generateReleaseResources (Thread[Daemon worker Thread 11,5,main]) started.
  :app:generateReleaseResources
  Skipping task ':app:generateReleaseResources' as it has no actions.
  :app:generateReleaseResources UP-TO-DATE
  :app:generateReleaseResources (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:mergeReleaseResources (Thread[Daemon worker Thread 11,5,main]) started.
  :app:mergeReleaseResources
  Skipping task ':app:mergeReleaseResources' as it is up-to-date (took 0.108 secs).
  :app:mergeReleaseResources UP-TO-DATE
  :app:mergeReleaseResources (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.108 secs.
  :app:processReleaseManifest (Thread[Daemon worker Thread 11,5,main]) started.
  :app:processReleaseManifest
  Skipping task ':app:processReleaseManifest' as it is up-to-date (took 0.003 secs).
  :app:processReleaseManifest UP-TO-DATE
  :app:processReleaseManifest (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.004 secs.
  :app:processReleaseResources (Thread[Daemon worker Thread 11,5,main]) started.
  :app:processReleaseResources
  Skipping task ':app:processReleaseResources' as it is up-to-date (took 0.054 secs).
  :app:processReleaseResources UP-TO-DATE
  :app:processReleaseResources (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.056 secs.
  :app:generateReleaseSources (Thread[Daemon worker Thread 11,5,main]) started.
  :app:generateReleaseSources
  Skipping task ':app:generateReleaseSources' as it has no actions.
  :app:generateReleaseSources UP-TO-DATE
  :app:generateReleaseSources (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.0 secs.
  :app:processReleaseJavaRes (Thread[Daemon worker Thread 11,5,main]) started.
  :app:processReleaseJavaRes
  Skipping task ':app:processReleaseJavaRes' as it has no source files.
  :app:processReleaseJavaRes UP-TO-DATE
  :app:processReleaseJavaRes (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:compileReleaseJavaWithJavac (Thread[Daemon worker Thread 11,5,main]) started.
  :app:compileReleaseJavaWithJavac
  Skipping task ':app:compileReleaseJavaWithJavac' as it is up-to-date (took 0.032 secs).
  :app:compileReleaseJavaWithJavac UP-TO-DATE
  :app:compileReleaseJavaWithJavac (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.034 secs.
  :app:compileReleaseNdk (Thread[Daemon worker Thread 11,5,main]) started.
  :app:compileReleaseNdk
  Skipping task ':app:compileReleaseNdk' as it has no source files.
  :app:compileReleaseNdk UP-TO-DATE
  :app:compileReleaseNdk (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.001 secs.
  :app:compileReleaseSources (Thread[Daemon worker Thread 11,5,main]) started.
  :app:compileReleaseSources
  Skipping task ':app:compileReleaseSources' as it has no actions.
  :app:compileReleaseSources UP-TO-DATE
  :app:compileReleaseSources (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.0 secs.
  :app:proguardRelease (Thread[Daemon worker Thread 11,5,main]) started.
  :app:proguardRelease
  Skipping task ':app:proguardRelease' as it is up-to-date (took 0.018 secs).
  :app:proguardRelease UP-TO-DATE
  :app:proguardRelease (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.018 secs.
  :app:dexRelease (Thread[Daemon worker Thread 11,5,main]) started.
  :app:dexRelease
  Skipping task ':app:dexRelease' as it is up-to-date (took 0.016 secs).
  :app:dexRelease UP-TO-DATE
  :app:dexRelease (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.018 secs.
  :app:validateExternalOverrideSigning (Thread[Daemon worker Thread 11,5,main]) started.
  :app:validateExternalOverrideSigning
  Executing task ':app:validateExternalOverrideSigning' (up-to-date check took 0.0 secs) due to:
    Task has not declared any outputs.
  :app:validateExternalOverrideSigning (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.0 secs.
  :app:packageRelease (Thread[Daemon worker Thread 11,5,main]) started.
  :app:packageRelease
  Executing task ':app:packageRelease' (up-to-date check took 0.052 secs) due to:
    No history is available.
  All input files are considered out-of-date for incremental task ':app:packageRelease'.
  :app:packageRelease FAILED
  :app:packageRelease (Thread[Daemon worker Thread 11,5,main]) completed. Took 0.218 secs.
  
  FAILURE: Build failed with an exception.
  
  * What went wrong:
  Execution failed for task ':app:packageRelease'.
  &gt; Unable to compute hash of C:\Users\J\AndroidStudioProjects\A\app\build\intermediates\classes-proguard\release\classes.jar
  
  * Try:
  Run with --debug option to get more log output.
  
  * Exception is:
  org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:packageRelease'.
      at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:69)
      at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:46)
      at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:35)
      at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:64)
      at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
      at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:42)
      at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
      at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:53)
      at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
      at org.gradle.api.internal.AbstractTask.executeWithoutThrowingTaskFailure(AbstractTask.java:310)
      at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.executeTask(AbstractTaskPlanExecutor.java:79)
      at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.processTask(AbstractTaskPlanExecutor.java:63)
      at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.run(AbstractTaskPlanExecutor.java:51)
      at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:23)
      at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:88)
      at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:37)
      at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:62)
      at org.gradle.execution.DefaultBuildExecuter.access$200(DefaultBuildExecuter.java:23)
      at org.gradle.execution.DefaultBuildExecuter$2.proceed(DefaultBuildExecuter.java:68)
      at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:32)
      at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:62)
      at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:55)
      at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:149)
      at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:106)
      at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:86)
      at org.gradle.launcher.exec.InProcessBuildActionExecuter$DefaultBuildController.run(InProcessBuildActionExecuter.java:90)
      at org.gradle.tooling.internal.provider.runner.BuildModelActionRunner.run(BuildModelActionRunner.java:54)
      at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
      at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:41)
      at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:28)
      at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:49)
      at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
      at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
      at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:37)
      at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
      at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:26)
      at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
      at org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon.execute(RequestStopIfSingleUsedDaemon.java:34)
      at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
      at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:74)
      at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:72)
      at org.gradle.util.Swapper.swap(Swapper.java:38)
      at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:72)
      at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
      at org.gradle.launcher.daemon.server.health.DaemonHealthTracker.execute(DaemonHealthTracker.java:47)
      at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
      at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:66)
      at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
      at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
      at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:71)
      at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
      at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
      at org.gradle.launcher.daemon.server.health.HintGCAfterBuild.execute(HintGCAfterBuild.java:41)
      at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
      at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:50)
      at org.gradle.launcher.daemon.server.DaemonStateCoordinator$1.run(DaemonStateCoordinator.java:246)
      at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:54)
      at org.gradle.internal.concurrent.StoppableExecutorImpl$1.run(StoppableExecutorImpl.java:40)
  Caused by: org.gradle.tooling.BuildException: Unable to compute hash of C:\Users\J\AndroidStudioProjects\A\app\build\intermediates\classes-proguard\release\classes.jar
      at com.android.build.gradle.tasks.PackageApplication.doFullTaskAction(PackageApplication.java:226)
      at com.android.build.gradle.internal.tasks.IncrementalTask.taskAction(IncrementalTask.java:79)
      at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:75)
      at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$IncrementalTaskAction.doExecute(AnnotationProcessingTaskFactory.java:243)
      at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:219)
      at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$IncrementalTaskAction.execute(AnnotationProcessingTaskFactory.java:230)
      at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:208)
      at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:80)
      at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:61)
      ... 57 more
  Caused by: com.android.builder.packaging.PackagerException: Unable to compute hash of C:\Users\J\AndroidStudioProjects\A\app\build\intermediates\classes-proguard\release\classes.jar
      at com.android.builder.core.AndroidBuilder.packageApk(AndroidBuilder.java:1808)
      at com.android.build.gradle.tasks.PackageApplication.doFullTaskAction(PackageApplication.java:206)
      ... 65 more
  
  
  BUILD FAILED
  
  Total time: 1.141 secs
  Stopped 0 compiler daemon(s).
  </code></pre>
  
  <p>I never before had such a strange error and it only occurs if I enable proguard for minifying my project. But obviously I need proguard since I want to obfusicate my code in release situations.</p>
  
  <p>Has anybody else experienced such an error? What can I do? I built the project some time ago perfectly fine with the same settings and minfiying on. My proguard file btw is completly empty.</p>
  
  <p>Thanks for any help. </p>