Android exception while building App with proguard

Question

I want to use proguard to change name of one DigestUtils class to overcome this problem Method not found using DigestUtils in Android . This is proguard-rules.pro file (only one line, obfuscate only one file):

-keep class !org.apache.commons.codec.digest.DigestUtils,** { *; }

This is app build.gradle file:

android {
    compileSdkVersion 26
    buildToolsVersion "29.0.2"

    defaultConfig {
        minSdkVersion 17
        targetSdkVersion 26

        multiDexEnabled true
    }

    buildTypes {
        debug {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }

then if I try to run ./gradlew assembleDebug --stacktrace I get this exception:

R8: Missing class: org.osgi.framework.SynchronousBundleListener

> Task :app:transformClassesAndResourcesWithR8ForDebug FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:transformClassesAndResourcesWithR8ForDebug'.
> java.lang.NullPointerException (no error message)

* Try:
Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:transformClassesAndResourcesWithR8ForDebug'.
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:151)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:148)
        at org.gradle.internal.Try$Failure.ifSuccessfulOrElse(Try.java:191)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:141)
        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$1.run(ManagedExecutorImpl.java:46)
        at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
Caused by: java.lang.NullPointerException
        at com.android.tools.r8.s.d.a(:15)
        at com.android.tools.r8.s.d.a(:21)
        at com.android.tools.r8.s.d.a(:9)
        at com.android.tools.r8.s.d.a(:77)
        at com.android.tools.r8.s.d.a(:178)
        at com.android.tools.r8.R8.a(:223)
        at com.android.tools.r8.R8.c(:1)
        at com.android.tools.r8.R8.b(:1)
        at com.android.tools.r8.utils.t.a(:23)
        at com.android.tools.r8.R8.runForTesting(:3)
        at com.android.tools.r8.R8.run(:3)
        at com.android.builder.dexing.R8Tool.runR8(r8Tool.kt:199)
        at com.android.build.gradle.internal.transforms.R8Transform.transform(R8Transform.kt:261)
        at com.android.build.gradle.internal.pipeline.TransformTask$2.call(TransformTask.java:239)
        at com.android.build.gradle.internal.pipeline.TransformTask$2.call(TransformTask.java:235)
        at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:106)
        at com.android.build.gradle.internal.pipeline.TransformTask.transform(TransformTask.java:230)
        at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:103)
        at org.gradle.api.internal.project.taskfactory.IncrementalTaskInputsTaskAction.doExecute(IncrementalTaskInputsTaskAction.java:46)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:41)
        at org.gradle.api.internal.project.taskfactory.AbstractIncrementalTaskAction.execute(AbstractIncrementalTaskAction.java:25)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:28)
        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$0(ExecuteStep.java:32)
        at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:32)
        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 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)
        ... 35 more

Answer 1

It is not possible to use R8 to address this problem. Even when org.apache.commons.codec.digest.DigestUtils is renamed, it will still use org.apache.commons.codec.binary.Hex from the Android framework, which does not include the method encodeHexString . See https://stackoverflow.com/a/29833101/2418642 for the details.

You will need to use a tool like Shadow to repackage your own version of commons-codec.