Conflicts with xerces

i am trying to run this code in a plugin

def pomFiles = new FileNameFinder().getFileNames(repoPath.absolutePath, '**/*.pom')

and im getting this exception

: java.lang.ClassCastException: org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
	at groovy.util.AntBuilder.performTask(AntBuilder.java:340)
	at groovy.util.AntBuilder.nodeCompleted(AntBuilder.java:272)
	at groovy.util.BuilderSupport.doInvokeMethod(BuilderSupport.java:154)
	at groovy.util.AntBuilder.doInvokeMethod(AntBuilder.java:207)
	at groovy.util.BuilderSupport.invokeMethod(BuilderSupport.java:67)
	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:48)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
	at groovy.util.FileNameFinder.getFileNames(FileNameFinder.groovy:40)
	at groovy.util.FileNameFinder$getFileNames.callCurrent(Unknown Source)
	at groovy.util.FileNameFinder.getFileNames(FileNameFinder.groovy:31)
	at groovy.util.IFileNameFinder$getFileNames.call(Unknown Source)
	at com.hmhs.frameworks.syzygy.gradle.artie.lang.python.PythonThirdPartyImportHelper.deployFiles(PythonThirdPartyImportHelper.groovy:87)
	at com.hmhs.frameworks.syzygy.gradle.artie.lang.python.PythonThirdPartyImportHelper$deployFiles$3.call(Unknown Source)
	at com.hmhs.frameworks.syzygy.gradle.artie.lang.PythonThirdPartyProcessor.uploadArtifacts(PythonThirdPartyProcessor.groovy:79)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:384)
	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1022)
	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.callCurrent(PogoMetaClassSite.java:69)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:190)
	at com.hmhs.frameworks.syzygy.gradle.artie.lang.PythonThirdPartyProcessor$_processFile_closure1.doCall(PythonThirdPartyProcessor.groovy:34)
	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.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1022)
	at groovy.lang.Closure.call(Closure.java:414)
	at org.codehaus.groovy.runtime.DefaultGroovyMethods.callClosureForMapEntry(DefaultGroovyMethods.java:5276)
	at org.codehaus.groovy.runtime.DefaultGroovyMethods.each(DefaultGroovyMethods.java:2117)
	at org.codehaus.groovy.runtime.dgm$164.invoke(Unknown Source)
	at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:274)
	at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:56)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
	at com.hmhs.frameworks.syzygy.gradle.artie.lang.PythonThirdPartyProcessor.processFile(PythonThirdPartyProcessor.groovy:30)
	at com.hmhs.frameworks.syzygy.gradle.artie.lang.LanguageProcessor$processFile$0.call(Unknown Source)
	at com.hmhs.frameworks.syzygy.gradle.artie.tasks.DownloadMetadataTask.processArtifacts(DownloadMetadataTask.groovy:64)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
	at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:46)
	at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:39)
	at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:26)
	at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:780)
	at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:747)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:121)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$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:110)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:92)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:70)
	at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
	at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:62)
	at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
	at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:60)
	at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:97)
	at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:87)
	at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:52)
	at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
	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$1.run(DefaultTaskGraphExecuter.java:248)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$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:241)
	at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:230)
	at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$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$1.execute(DefaultTaskPlanExecutor.java:98)
	at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:626)
	at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:581)
	at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
	at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:59)
	at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:128)
	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:314)
	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:204)
	at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:134)
	at org.gradle.initialization.DefaultGradleLauncher.executeTasks(DefaultGradleLauncher.java:109)
	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.BuildModelActionRunner.run(BuildModelActionRunner.java:53)
	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:47)
	at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:30)
	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:69)
	at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:30)
	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$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassCastException: org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
	at org.apache.xerces.parsers.SAXParser.<init>(Unknown Source)
	at org.apache.xerces.parsers.SAXParser.<init>(Unknown Source)
	at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.<init>(Unknown Source)
	at org.apache.xerces.jaxp.SAXParserImpl.<init>(Unknown Source)
	at org.apache.xerces.jaxp.SAXParserFactoryImpl.newSAXParser(Unknown Source)
	at org.apache.tools.ant.util.JAXPUtils.newSAXParser(JAXPUtils.java:217)
	at org.apache.tools.ant.util.JAXPUtils.getNamespaceXMLReader(JAXPUtils.java:174)
	at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:245)
	at org.apache.tools.ant.helper.ProjectHelper2.parseUnknownElement(ProjectHelper2.java:131)
	at org.apache.tools.ant.helper.ProjectHelper2.parseAntlibDescriptor(ProjectHelper2.java:111)
	at org.apache.tools.ant.taskdefs.Antlib.createAntlib(Antlib.java:94)
	at org.apache.tools.ant.taskdefs.Definer.loadAntlib(Definer.java:425)
	at org.apache.tools.ant.taskdefs.Definer.execute(Definer.java:277)
	at org.apache.tools.ant.ComponentHelper.checkNamespace(ComponentHelper.java:874)
	at org.apache.tools.ant.ComponentHelper.getDefinition(ComponentHelper.java:307)
	at org.apache.tools.ant.ComponentHelper.createComponent(ComponentHelper.java:284)
	at org.apache.tools.ant.ComponentHelper.createComponent(ComponentHelper.java:263)
	at org.apache.tools.ant.UnknownElement.makeObject(UnknownElement.java:430)
	at org.apache.tools.ant.UnknownElement.maybeConfigure(UnknownElement.java:164)
	at groovy.util.AntBuilder.performTask(AntBuilder.java:322)
	... 166 more

Seems like a classic class collision problem. i tried adding a resolutionStrategy to the project in order to force version 2.9.1 of xerces (thats the only one i can find in my dependency maps). any idea how to fix this?

I just had the same problem and finally found a fix.
Some of build script dependencies have xerces transitive dependency.
If this would be a compile dependency, you would trace the culprit and add exclude to it, like this:

compile('com.netflix.nebula:gradle-dependency-lock-plugin:5.0.4') {
  exclude group: 'xerces', module: 'xercesImpl'
}

But this doesn’t work with buildscript dependencies, see https://issues.gradle.org/browse/GRADLE-1478.

This code in buildscript works:

buildscript {
  dependencies {
    configurations.classpath.exclude group: 'xerces', module: 'xercesImpl'
  }
}