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Bug 313490

Summary:

ConcurrentModificationException during synchronizing artifact repository (p2.directorywatcher)

Product:

[Eclipse Project] Equinox

Reporter:

Katya Stoycheva <katya.stoycheva>

Component:

Assignee:

DJ Houghton <dj.houghton>

Status:

RESOLVED FIXED

QA Contact:

Severity:

normal

Priority:

CC:

pascal, thomas

Version:

unspecified

Flags:

dj.houghton: review+
thomas: review+

Target Milestone:

3.6 RC2

Hardware:

OS:

Windows XP

Whiteboard:

Attachments:

Description	Flags
structure traversal with iterator is replaced with iterating array copy of the structure	dj.houghton: iplog+

Description Katya Stoycheva

2010-05-19 05:22:06 EDT

Build Identifier: 3.6.0.N20100512-2000

When synchronizing artifact repository (triggered by adding a bundle in dropins folder), ConcurrentModificationException is produced because of modifying underlying structure after the iterator is obtained.

Here is the code that cause the exception (synchronizeArtifactRepository method):
...
if (removedFiles.contains(artifactFile))		   			            artifactRepository.removeDescriptor(descriptor);
...

Reproducible: Always

Steps to Reproduce:
1.Download and unzip Equinox (http://download.eclipse.org/equinox/drops/N20100512-2000/index.php)
2.Start it in root folder (equinox) using 
java -jar plugins/org.eclipse.osgi_3.6.0.N20100512-2000.jar -configuration configuration –console
3.Setup dropins folder in config.ini:
org.eclipse.equinox.p2.reconciler.dropins.directory=dropins
4.Describe all plugins (and start them) in 
Equinox/configuration/org.eclipse.equinox.simpleconfigurator/bundles.info
5.Add some plugins in dropins folder
6.When dropins reconciler is started, observe the ConcurrentModificationException in logs:
!ENTRY org.eclipse.equinox.p2.reconciler.dropins 4 0 2010-05-14 16:11:44.463
!MESSAGE 
!STACK 0
org.osgi.framework.BundleException: Exception in org.eclipse.equinox.internal.p2.reconciler.dropins.Activator.start() of bundle org.eclipse.equinox.p2.reconciler.dropins.
	at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:806)
	at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:755)
	at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:370)
	at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.java:374)
	at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java:1067)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:561)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:546)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:459)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:243)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:440)
	at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:227)
	at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:337)
Caused by: java.util.ConcurrentModificationException
	at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
	at java.util.AbstractList$Itr.next(Unknown Source)
	at org.eclipse.equinox.internal.p2.metadata.expression.RepeatableIterator.next(RepeatableIterator.java:82)
	at org.eclipse.equinox.internal.p2.metadata.expression.CompoundIterator.positionNext(CompoundIterator.java:76)
	at org.eclipse.equinox.internal.p2.metadata.expression.CompoundIterator.hasNext(CompoundIterator.java:43)
	at org.eclipse.equinox.internal.p2.metadata.expression.CompoundIterator.positionNext(CompoundIterator.java:69)
	at org.eclipse.equinox.internal.p2.metadata.expression.CompoundIterator.hasNext(CompoundIterator.java:43)
	at org.eclipse.equinox.internal.p2.metadata.expression.RepeatableIterator$IndexProviderIterator.hasNext(RepeatableIterator.java:142)
	at org.eclipse.equinox.internal.provisional.p2.directorywatcher.RepositoryListener.synchronizeArtifactRepository(RepositoryListener.java:241)
	at org.eclipse.equinox.internal.provisional.p2.directorywatcher.RepositoryListener.stopPoll(RepositoryListener.java:199)
	at org.eclipse.equinox.internal.p2.reconciler.dropins.DropinsRepositoryListener.stopPoll(DropinsRepositoryListener.java:236)
	at org.eclipse.equinox.internal.provisional.p2.directorywatcher.DirectoryWatcher.stopPoll(DirectoryWatcher.java:171)
	at org.eclipse.equinox.internal.provisional.p2.directorywatcher.DirectoryWatcher.poll(DirectoryWatcher.java:109)
	at org.eclipse.equinox.internal.p2.reconciler.dropins.Activator.watchDropins(Activator.java:476)
	at org.eclipse.equinox.internal.p2.reconciler.dropins.Activator.start(Activator.java:160)
	at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:783)
	at java.security.AccessController.doPrivileged(Native Method)
	at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:774)
	... 11 more
Root exception:
java.util.ConcurrentModificationException
	at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
	at java.util.AbstractList$Itr.next(Unknown Source)
	at org.eclipse.equinox.internal.p2.metadata.expression.RepeatableIterator.next(RepeatableIterator.java:82)
	at org.eclipse.equinox.internal.p2.metadata.expression.CompoundIterator.positionNext(CompoundIterator.java:76)
	at org.eclipse.equinox.internal.p2.metadata.expression.CompoundIterator.hasNext(CompoundIterator.java:43)
	at org.eclipse.equinox.internal.p2.metadata.expression.CompoundIterator.positionNext(CompoundIterator.java:69)
	at org.eclipse.equinox.internal.p2.metadata.expression.CompoundIterator.hasNext(CompoundIterator.java:43)
	at org.eclipse.equinox.internal.p2.metadata.expression.RepeatableIterator$IndexProviderIterator.hasNext(RepeatableIterator.java:142)
	at org.eclipse.equinox.internal.provisional.p2.directorywatcher.RepositoryListener.synchronizeArtifactRepository(RepositoryListener.java:241)
	at org.eclipse.equinox.internal.provisional.p2.directorywatcher.RepositoryListener.stopPoll(RepositoryListener.java:199)
	at org.eclipse.equinox.internal.p2.reconciler.dropins.DropinsRepositoryListener.stopPoll(DropinsRepositoryListener.java:236)
	at org.eclipse.equinox.internal.provisional.p2.directorywatcher.DirectoryWatcher.stopPoll(DirectoryWatcher.java:171)
	at org.eclipse.equinox.internal.provisional.p2.directorywatcher.DirectoryWatcher.poll(DirectoryWatcher.java:109)
	at org.eclipse.equinox.internal.p2.reconciler.dropins.Activator.watchDropins(Activator.java:476)
	at org.eclipse.equinox.internal.p2.reconciler.dropins.Activator.start(Activator.java:160)
	at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:783)
	at java.security.AccessController.doPrivileged(Native Method)
	at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:774)
	at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:755)
	at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:370)
	at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.java:374)
	at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java:1067)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:561)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:546)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:459)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:243)
	at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:440)
	at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:227)
	at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:337)

Comment 1 Katya Stoycheva

2010-05-19 05:25:39 EDT

Created attachment 169075 [details]
structure traversal with iterator is replaced with iterating array copy of the structure

May result in slight increasing memory consumption due to array copy

Comment 2 Pascal Rapicault

2010-05-19 22:20:11 EDT

I'm surprised that we have not yet run into this. I've looked at the patch and it looks good.

Comment 3 DJ Houghton

2010-05-20 14:32:27 EDT

Thanks for the patch! 
Fix released.