原因：尝试运行 Android 项目时出现 java.lang.NullPointerException（通过 Android Studio）

Question

运行项目时出现以下错误（ app:transformClassesWithInstantRunForDebug ）。 这个项目之前运行良好。 除了 xml 布局文件外，我没有更新项目中的任何内容。

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:transformClassesWithInstantRunForDebug'.
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:103)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:73)
at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:59)
at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:59)
at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:101)
at org.gradle.api.internal.tasks.execution.FinalizeInputFilePropertiesTaskExecuter.execute(FinalizeInputFilePropertiesTaskExecuter.java:44)
at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:91)
at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:62)
at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:59)
at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:256)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:249)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:238)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:123)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:79)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:104)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:98)
at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:663)
at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:597)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:59)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:130)
at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:37)
at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
at org.gradle.execution.DefaultBuildExecuter.access$000(DefaultBuildExecuter.java:23)
at org.gradle.execution.DefaultBuildExecuter$1.proceed(DefaultBuildExecuter.java:43)
at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:46)
at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:30)
at org.gradle.initialization.DefaultGradleLauncher$ExecuteTasks.run(DefaultGradleLauncher.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
at org.gradle.initialization.DefaultGradleLauncher.runTasks(DefaultGradleLauncher.java:210)
at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:140)
at org.gradle.initialization.DefaultGradleLauncher.executeTasks(DefaultGradleLauncher.java:115)
at org.gradle.internal.invocation.GradleBuildController$1.call(GradleBuildController.java:78)
at org.gradle.internal.invocation.GradleBuildController$1.call(GradleBuildController.java:75)
at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:152)
at org.gradle.internal.invocation.GradleBuildController.doBuild(GradleBuildController.java:100)
at org.gradle.internal.invocation.GradleBuildController.run(GradleBuildController.java:75)
at org.gradle.tooling.internal.provider.runner.ClientProvidedBuildActionRunner.run(ClientProvidedBuildActionRunner.java:62)
at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
at org.gradle.tooling.internal.provider.ValidatingBuildActionRunner.run(ValidatingBuildActionRunner.java:32)
at org.gradle.launcher.exec.RunAsBuildOperationBuildActionRunner$1.run(RunAsBuildOperationBuildActionRunner.java:43)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
at org.gradle.launcher.exec.RunAsBuildOperationBuildActionRunner.run(RunAsBuildOperationBuildActionRunner.java:40)
at org.gradle.tooling.internal.provider.SubscribableBuildActionRunner.run(SubscribableBuildActionRunner.java:51)
at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:49)
at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:32)
at org.gradle.launcher.exec.BuildTreeScopeBuildActionExecuter.execute(BuildTreeScopeBuildActionExecuter.java:39)
at org.gradle.launcher.exec.BuildTreeScopeBuildActionExecuter.execute(BuildTreeScopeBuildActionExecuter.java:25)
at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:80)
at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:53)
at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:57)
at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:32)
at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:36)
at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:25)
at org.gradle.tooling.internal.provider.ParallelismConfigurationBuildActionExecuter.execute(ParallelismConfigurationBuildActionExecuter.java:43)
at org.gradle.tooling.internal.provider.ParallelismConfigurationBuildActionExecuter.execute(ParallelismConfigurationBuildActionExecuter.java:29)
at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:64)
at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:29)
at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:59)
at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:44)
at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:45)
at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:30)
at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:67)
at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:37)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:26)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
at org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon.execute(RequestStopIfSingleUsedDaemon.java:34)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
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:122)
at org.gradle.launcher.daemon.server.exec.LogAndCheckHealth.execute(LogAndCheckHealth.java:55)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:62)
at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:82)
at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:50)
at org.gradle.launcher.daemon.server.DaemonStateCoordinator$1.run(DaemonStateCoordinator.java:295)
at org.gradle.internal.concurrent.ExecutorPolicy$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$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: com.android.build.api.transform.TransformException: java.lang.NullPointerException
    at com.android.builder.profile.Recorder$Block.handleException(Recorder.java:55)
    at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:104)
    at com.android.build.gradle.internal.pipeline.TransformTask.transform(TransformTask.java:230)
    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:73)
    at org.gradle.api.internal.project.taskfactory.IncrementalTaskAction.doExecute(IncrementalTaskAction.java:50)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:39)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:26)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:124)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:113)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:95)
    ... 108 more
Caused by: com.android.build.api.transform.TransformException: java.lang.NullPointerException
    at com.android.build.gradle.internal.transforms.InstantRunTransform.doTransform(InstantRunTransform.java:320)
    at com.android.build.gradle.internal.transforms.InstantRunTransform.transform(InstantRunTransform.java:186)
    at com.android.build.gradle.internal.pipeline.TransformTask$2.call(TransformTask.java:239)
    at com.android.build.gradle.internal.pipeline.TransformTask$2.call(TransformTask.java:235)
    at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:102)
    ... 124 more
Caused by: java.lang.NullPointerException
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.util.concurrent.ForkJoinTask.getThrowableException(ForkJoinTask.java:598)
    at java.util.concurrent.ForkJoinTask.reportException(ForkJoinTask.java:677)
    at java.util.concurrent.ForkJoinTask.join(ForkJoinTask.java:720)
    at com.android.ide.common.internal.WaitableExecutor.waitForTasksWithQuickFail(WaitableExecutor.java:146)
    at com.android.build.gradle.internal.transforms.InstantRunTransform.doTransform(InstantRunTransform.java:315)
    ... 128 more
Caused by: java.lang.NullPointerException
    at com.android.build.gradle.internal.incremental.ConstructorBuilder.build(ConstructorBuilder.java:175)
    at com.android.build.gradle.internal.incremental.IncrementalSupportVisitor.visitMethod(IncrementalSupportVisitor.java:223)
    at org.objectweb.asm.ClassVisitor.visitMethod(ClassVisitor.java:327)
    at org.objectweb.asm.commons.SerialVersionUIDAdder.visitMethod(SerialVersionUIDAdder.java:255)
    at org.objectweb.asm.tree.MethodNode.accept(MethodNode.java:724)
    at org.objectweb.asm.tree.ClassNode.accept(ClassNode.java:452)
    at com.android.build.gradle.internal.incremental.IncrementalVisitor.instrumentClass(IncrementalVisitor.java:365)
    at com.android.build.gradle.internal.transforms.InstantRunTransform.transformToClasses2Format(InstantRunTransform.java:414)
    at com.android.build.gradle.internal.transforms.InstantRunTransform.lambda$doTransform$4(InstantRunTransform.java:276)
    at com.android.build.gradle.internal.transforms.InstantRunTransform.lambda$null$5(InstantRunTransform.java:305)
    at java.util.concurrent.ForkJoinTask$AdaptedCallable.exec(ForkJoinTask.java:1424)
    at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
    at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
    at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
    at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

到目前为止我做了什么。

我看到了一些类似的问题并做了同样的事情。

1. 清理项目

2. 重建.gradle

3. 重建项目

4. 最后但并非最不重要的是使缓存无效/重新启动

关于项目：

compileSdk版本27

buildToolsVersion '28.0.3'

multiDexEnabled 真

我不知道为什么要得到这个。 如果有任何解决办法，请告诉我。 任何帮助将不胜感激。

Answer 1

文件 -> 重新启动 IDE 现在享受