Licenser tasks fail the second time with configuration cache

[joschi]

When using the Gradle configuration cache, the tasks of the Licenser plugin (version 0.6.1) can only be executed once.

The second time fails with an error message:

Output with error message when running checkLicense task twice and configuration cache is enabled

# ./gradlew --configuration-cache checkLicense
Configuration cache is an incubating feature.
Calculating task graph as no configuration cache is available for tasks: checkLicense

BUILD SUCCESSFUL in 622ms
1 actionable task: 1 executed
Configuration cache entry stored.

# ./gradlew --configuration-cache checkLicense
Configuration cache is an incubating feature.
Reusing configuration cache.

> Task :checkLicenseMain FAILED
Failed to check license header of src/main/java/licenser/Library.java
java.lang.NullPointerException: Cannot get property 'java' on null object
        at org.codehaus.groovy.runtime.NullObject.getProperty(NullObject.java:60)
        at org.codehaus.groovy.runtime.InvokerHelper.getProperty(InvokerHelper.java:194)
        at org.codehaus.groovy.runtime.DefaultGroovyMethods.getAt(DefaultGroovyMethods.java:407)
        at org.codehaus.groovy.runtime.dgm$305.invoke(Unknown Source)
        at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoMetaMethodSiteNoUnwrapNoCoerce.invoke(PogoMetaMethodSite.java:226)
        at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.call(PogoMetaMethodSite.java:73)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
        at org.codehaus.groovy.runtime.callsite.NullCallSite.call(NullCallSite.java:34)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
        at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.call(PogoMetaMethodSite.java:78)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:139)
        at org.cadixdev.gradle.licenser.header.Header.prepare(Header.groovy:96)
        at org.cadixdev.gradle.licenser.header.Header$prepare$1.callCurrent(Unknown Source)
        at org.cadixdev.gradle.licenser.header.Header.prepare(Header.groovy:100)
        at org.cadixdev.gradle.licenser.header.Header$prepare$0.call(Unknown Source)
        at org.cadixdev.gradle.licenser.tasks.LicenseTask.prepareMatchingHeader(LicenseTask.groovy:104)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:107)
        at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:323)
        at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:351)
        at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.callCurrent(PogoMetaClassSite.java:61)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:194)
        at org.cadixdev.gradle.licenser.tasks.LicenseCheck$_checkFiles_closure1.doCall(LicenseCheck.groovy:61)
        at jdk.internal.reflect.GeneratedMethodAccessor120.invoke(Unknown Source)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:107)
        at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:323)
        at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:263)
        at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1035)
        at groovy.lang.Closure.call(Closure.java:412)
        at org.codehaus.groovy.runtime.ConvertedClosure.invokeCustom(ConvertedClosure.java:50)
        at org.codehaus.groovy.runtime.ConversionHandler.invoke(ConversionHandler.java:110)
        at com.sun.proxy.$Proxy83.visitFile(Unknown Source)
        at org.gradle.api.internal.file.collections.DefaultDirectoryWalker$PathVisitor.visitFile(DefaultDirectoryWalker.java:115)
        at org.gradle.api.internal.file.collections.DefaultDirectoryWalker$PathVisitor.visitFile(DefaultDirectoryWalker.java:68)
        at java.base/java.nio.file.Files.walkFileTree(Files.java:2725)
        at org.gradle.api.internal.file.collections.DefaultDirectoryWalker.walkDir(DefaultDirectoryWalker.java:62)
        at org.gradle.api.internal.file.collections.DirectoryFileTree.walkDir(DirectoryFileTree.java:149)
        at org.gradle.api.internal.file.collections.DirectoryFileTree.visitFrom(DirectoryFileTree.java:127)
        at org.gradle.api.internal.file.collections.DirectoryFileTree.visit(DirectoryFileTree.java:112)
        at org.gradle.api.internal.file.collections.FileTreeAdapter.visit(FileTreeAdapter.java:90)
        at org.gradle.api.internal.file.CompositeFileTree.visit(CompositeFileTree.java:102)
        at org.gradle.api.internal.file.CompositeFileTree.visit(CompositeFileTree.java:88)
        at org.gradle.api.file.FileTree$visit.call(Unknown Source)
        at org.cadixdev.gradle.licenser.tasks.LicenseCheck.checkFiles(LicenseCheck.groovy:55)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:104)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:58)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:51)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:29)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$2.run(ExecuteActionsTaskExecuter.java:506)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:75)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:68)
        at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:153)
        at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:68)
        at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:56)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.lambda$run$1(DefaultBuildOperationExecutor.java:74)
        at org.gradle.internal.operations.UnmanagedBuildOperationWrapper.runWithUnmanagedSupport(UnmanagedBuildOperationWrapper.java:45)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:74)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:491)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:474)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.access$300(ExecuteActionsTaskExecuter.java:106)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$TaskExecution.executeWithPreviousOutputFiles(ExecuteActionsTaskExecuter.java:271)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$TaskExecution.execute(ExecuteActionsTaskExecuter.java:249)
        at org.gradle.internal.execution.steps.ExecuteStep.executeInternal(ExecuteStep.java:83)
        at org.gradle.internal.execution.steps.ExecuteStep.access$000(ExecuteStep.java:37)
        at org.gradle.internal.execution.steps.ExecuteStep$1.call(ExecuteStep.java:50)
        at org.gradle.internal.execution.steps.ExecuteStep$1.call(ExecuteStep.java:47)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:200)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:195)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:75)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:68)
        at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:153)
        at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:68)
        at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:62)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.lambda$call$2(DefaultBuildOperationExecutor.java:79)
        at org.gradle.internal.operations.UnmanagedBuildOperationWrapper.callWithUnmanagedSupport(UnmanagedBuildOperationWrapper.java:54)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:79)
        at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:47)
        at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:37)
        at org.gradle.internal.execution.steps.RemovePreviousOutputsStep.execute(RemovePreviousOutputsStep.java:68)
        at org.gradle.internal.execution.steps.RemovePreviousOutputsStep.execute(RemovePreviousOutputsStep.java:38)
        at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:50)
        at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:36)
        at org.gradle.internal.execution.steps.CancelExecutionStep.execute(CancelExecutionStep.java:41)
        at org.gradle.internal.execution.steps.TimeoutStep.executeWithoutTimeout(TimeoutStep.java:74)
        at org.gradle.internal.execution.steps.TimeoutStep.execute(TimeoutStep.java:55)
        at org.gradle.internal.execution.steps.CreateOutputsStep.execute(CreateOutputsStep.java:51)
        at org.gradle.internal.execution.steps.CreateOutputsStep.execute(CreateOutputsStep.java:29)
        at org.gradle.internal.execution.steps.CaptureStateAfterExecutionStep.execute(CaptureStateAfterExecutionStep.java:54)
        at org.gradle.internal.execution.steps.CaptureStateAfterExecutionStep.execute(CaptureStateAfterExecutionStep.java:35)
        at org.gradle.internal.execution.steps.BroadcastChangingOutputsStep.execute(BroadcastChangingOutputsStep.java:60)
        at org.gradle.internal.execution.steps.BroadcastChangingOutputsStep.execute(BroadcastChangingOutputsStep.java:27)
        at org.gradle.internal.execution.steps.BuildCacheStep.executeWithoutCache(BuildCacheStep.java:174)
        at org.gradle.internal.execution.steps.BuildCacheStep.execute(BuildCacheStep.java:74)
        at org.gradle.internal.execution.steps.BuildCacheStep.execute(BuildCacheStep.java:45)
        at org.gradle.internal.execution.steps.StoreExecutionStateStep.execute(StoreExecutionStateStep.java:40)
        at org.gradle.internal.execution.steps.StoreExecutionStateStep.execute(StoreExecutionStateStep.java:29)
        at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:36)
        at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:22)
        at org.gradle.internal.execution.steps.SkipUpToDateStep.executeBecause(SkipUpToDateStep.java:99)
        at org.gradle.internal.execution.steps.SkipUpToDateStep.lambda$execute$0(SkipUpToDateStep.java:92)
        at java.base/java.util.Optional.map(Optional.java:265)
        at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:52)
        at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:36)
        at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:85)
        at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:42)
        at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:37)
        at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:27)
        at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:91)
        at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:49)
        at org.gradle.internal.execution.steps.ValidateStep.execute(ValidateStep.java:106)
        at org.gradle.internal.execution.steps.ValidateStep.execute(ValidateStep.java:51)
        at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.execute(CaptureStateBeforeExecutionStep.java:72)
        at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.execute(CaptureStateBeforeExecutionStep.java:46)
        at org.gradle.internal.execution.steps.SkipEmptyWorkStep.lambda$execute$2(SkipEmptyWorkStep.java:86)
        at java.base/java.util.Optional.orElseGet(Optional.java:369)
        at org.gradle.internal.execution.steps.SkipEmptyWorkStep.execute(SkipEmptyWorkStep.java:86)
        at org.gradle.internal.execution.steps.SkipEmptyWorkStep.execute(SkipEmptyWorkStep.java:32)
        at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsStartedStep.execute(MarkSnapshottingInputsStartedStep.java:38)
        at org.gradle.internal.execution.steps.LoadExecutionStateStep.execute(LoadExecutionStateStep.java:43)
        at org.gradle.internal.execution.steps.LoadExecutionStateStep.execute(LoadExecutionStateStep.java:31)
        at org.gradle.internal.execution.steps.AssignWorkspaceStep.lambda$execute$0(AssignWorkspaceStep.java:40)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$TaskExecution$2.withWorkspace(ExecuteActionsTaskExecuter.java:284)
        at org.gradle.internal.execution.steps.AssignWorkspaceStep.execute(AssignWorkspaceStep.java:40)
        at org.gradle.internal.execution.steps.AssignWorkspaceStep.execute(AssignWorkspaceStep.java:30)
        at org.gradle.internal.execution.steps.IdentityCacheStep.execute(IdentityCacheStep.java:37)
        at org.gradle.internal.execution.steps.IdentityCacheStep.execute(IdentityCacheStep.java:27)
        at org.gradle.internal.execution.steps.IdentifyStep.execute(IdentifyStep.java:44)
        at org.gradle.internal.execution.steps.IdentifyStep.execute(IdentifyStep.java:33)
        at org.gradle.internal.execution.impl.DefaultExecutionEngine$1.execute(DefaultExecutionEngine.java:76)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeIfValid(ExecuteActionsTaskExecuter.java:185)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:174)
        at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:109)
        at org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute(FinalizePropertiesTaskExecuter.java:46)
        at org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute(ResolveTaskExecutionModeExecuter.java:51)
        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:77)
        at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:55)
        at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:52)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:200)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:195)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:75)
        at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:68)
        at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:153)
        at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:68)
        at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:62)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.lambda$call$2(DefaultBuildOperationExecutor.java:79)
        at org.gradle.internal.operations.UnmanagedBuildOperationWrapper.callWithUnmanagedSupport(UnmanagedBuildOperationWrapper.java:54)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:79)
        at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute(EventFiringTaskExecuter.java:52)
        at org.gradle.execution.plan.LocalTaskNodeExecutor.execute(LocalTaskNodeExecutor.java:74)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:408)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:395)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:388)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:374)
        at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.lambda$run$0(DefaultPlanExecutor.java:127)
        at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute(DefaultPlanExecutor.java:191)
        at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.executeNextNode(DefaultPlanExecutor.java:182)
        at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run(DefaultPlanExecutor.java:124)
        at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
        at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
        at java.base/java.lang.Thread.run(Thread.java:834)

FAILURE: Build completed with 2 failures.

1: Task failed with an exception.
-----------
* What went wrong:
Execution failed for task ':checkLicenseMain'.
> License violations were found: src/main/java/licenser/Library.java

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
==============================================================================

2: Task failed with an exception.
-----------
* What went wrong:
Configuration cache problems found in this build.

2 problems were found reusing the configuration cache.
- Task `:checkLicenseMain` of type `org.cadixdev.gradle.licenser.tasks.LicenseCheck`: value '{fxml=XML, css=BLOCK_COMMENT, scala=BLOCK_COMMENT, xsd=XML, kt=BLOCK_COMMENT, js=BLOCK_COMMENT, kts=BLOCK_COMMENT, xhtml=XML, gradle=BLOCK_COMMENT, xsl=XML, java=BLOCK_COMMENT, groovy=BLOCK_COMMENT, sh=HASH, dtd=XML, xml=XML, yml=HASH, html=XML, properties=HASH, yaml=HASH}' is not assignable to 'org.cadixdev.gradle.licenser.header.HeaderFormatRegistry'
- Task `:checkLicenseTest` of type `org.cadixdev.gradle.licenser.tasks.LicenseCheck`: value '{fxml=XML, css=BLOCK_COMMENT, scala=BLOCK_COMMENT, xsd=XML, kt=BLOCK_COMMENT, js=BLOCK_COMMENT, kts=BLOCK_COMMENT, xhtml=XML, gradle=BLOCK_COMMENT, xsl=XML, java=BLOCK_COMMENT, groovy=BLOCK_COMMENT, sh=HASH, dtd=XML, xml=XML, yml=HASH, html=XML, properties=HASH, yaml=HASH}' is not assignable to 'org.cadixdev.gradle.licenser.header.HeaderFormatRegistry'

See the complete report at file:///Users/joschi/licenser/build/reports/configuration-cache/2ktvk4o9qbjko0p4znlgb06m/configuration-cache-report.html

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
==============================================================================

* Get more help at https://help.gradle.org

BUILD FAILED in 593ms
1 actionable task: 1 executed
Configuration cache entry reused with 2 problems.

Gradle project to reproduce the issue:

build.gradle:

plugins {
    id 'java-library'
    id "org.cadixdev.licenser" version "0.6.1"
}

LICENSE:

My license

src/main/java/licenser/Library.java:

/*
 * My license
 */

/*
 * This Java source file was generated by the Gradle 'init' task.
 */
package licenser;

public class Library {
    public boolean someLibraryMethod() {
        return true;
    }
}

Reproducing command:

./gradlew --configuration-cache checkLicense && ./gradlew --configuration-cache checkLicense