ConcurrentModificationException in ConfigurationClassParser.processDeferredImportSelectors [SPR-11997]

[spring-projects-issues]

Andy Wilkinson opened SPR-11997 and commented

I'm trying Spring Boot against the 4.1.0 snapshots and two tests that use a parent-child context hierarchy are failing with the same ConcurrentModificationException:

java.util.ConcurrentModificationException
	at java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:761)
	at java.util.LinkedList$ListItr.next(LinkedList.java:696)
	at org.springframework.context.annotation.ConfigurationClassParser.processDeferredImportSelectors(ConfigurationClassParser.java:388)
	at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:165)
	at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:305)
	at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:243)
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:254)
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:94)
	at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:604)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:462)
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:120)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:691)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:320)
	at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:142)
	at org.springframework.boot.actuate.autoconfigure.SpringApplicationHierarchyTests.testChild(SpringApplicationHierarchyTests.java:49)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

The cause of the concurrent modification appears to be in processImports which is called while looping over this.deferredImportSelectors. processImports may call this.deferredImportSelectors.add() which results in the ConcurrentModificationException being thrown the next time round the loop.

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Affects: 4.1 RC1

Issue Links:

• #17436 ConcurrentModificationException in ConfigurationClassParser.processDeferredImportSelectors

Referenced from: commits bbf5800

[spring-projects-issues]

Juergen Hoeller commented

This seems to have been caused by the presence of our ViewConfigurationImportSelector which went away for other reasons in the meantime...

Nevertheless, this issue indicates a problem with any DeferredImportSelector which in turn imports another DeferredImportSelector. We're processing the latter as regular import selectors now, not adding them to that deferred List to begin with.

In the course of this, I've also refined the exception handling in ConfigurationClassParser, treating regular class loading and ASM-based loading consistently in terms of exception wrapping, and always mentioning the current configuration class in its messages.

Juergen