[jira] [Commented] (FELIX-4609) Possible ConcurrentModificationException in WatcherScanner
[
https://issues.apache.org/jira/browse/FELIX-4609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14126926#comment-14126926
]
Jean-Baptiste Onofré commented on FELIX-4609:
-
I submitted a patch in FELIX-4532 fixing the problem.
> Possible ConcurrentModificationException in WatcherScanner
> --
>
> Key: FELIX-4609
> URL: https://issues.apache.org/jira/browse/FELIX-4609
> Project: Felix
> Issue Type: Bug
> Components: File Install
>Affects Versions: fileinstall-3.4.0
>Reporter: Daniel Kulp
>
> In some cases at startup, I'm getting:
> {code}
> 12:02:06,941 | ERROR | OT/container/etc | ?
> ? | 6 - org.apache.felix.fileinstall - 3.4.0 | In main loop, we have serious
> trouble
> java.util.ConcurrentModificationException
> at java.util.HashMap$HashIterator.nextEntry(HashMap.java:922)[:1.7.0_67]
> at java.util.HashMap$KeyIterator.next(HashMap.java:956)[:1.7.0_67]
> at
> org.apache.felix.fileinstall.internal.WatcherScanner.scan(WatcherScanner.java:70)[6:org.apache.felix.fileinstall:3.4.0]
> at
> org.apache.felix.fileinstall.internal.DirectoryWatcher.run(DirectoryWatcher.java:305)[6:org.apache.felix.fileinstall:3.4.0]
> {code}
> The problem looks to stem from line 83 of WatcherScanner. The "changed"
> HashSet is being modified (remove call) within the for loop that is iterating
> over it.
> Most likely, a small change of:
> {code}
> Index: WatcherScanner.java
> ===
> --- WatcherScanner.java (revision 1619096)
> +++ WatcherScanner.java (working copy)
> @@ -78,10 +78,8 @@
> if ((newChecksum == lastChecksum || reportImmediately)) {
> if (newChecksum != storedChecksum) {
> storedChecksums.put(file, newChecksum);
> -files.add(file);
> -} else {
> -changed.remove(file);
> }
> +files.add(file);
> if (reportImmediately) {
> removed.remove(file);
> }
> {code}
> will fix it, but untested at this point.
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[jira] [Commented] (FELIX-4609) Possible ConcurrentModificationException in WatcherScanner
[
https://issues.apache.org/jira/browse/FELIX-4609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14118233#comment-14118233
]
Andre Flakowski commented on FELIX-4609:
I reproduced the problem under Karaf 2.3.6 as well.
I traced it back to the same Issue: The problem is the removal of a config file
in line 83 (changed.remove(file);) which causes the HashMap to throw the
ConcurrentModificationException.
> Possible ConcurrentModificationException in WatcherScanner
> --
>
> Key: FELIX-4609
> URL: https://issues.apache.org/jira/browse/FELIX-4609
> Project: Felix
> Issue Type: Bug
> Components: File Install
>Affects Versions: fileinstall-3.4.0
>Reporter: Daniel Kulp
>
> In some cases at startup, I'm getting:
> {code}
> 12:02:06,941 | ERROR | OT/container/etc | ?
> ? | 6 - org.apache.felix.fileinstall - 3.4.0 | In main loop, we have serious
> trouble
> java.util.ConcurrentModificationException
> at java.util.HashMap$HashIterator.nextEntry(HashMap.java:922)[:1.7.0_67]
> at java.util.HashMap$KeyIterator.next(HashMap.java:956)[:1.7.0_67]
> at
> org.apache.felix.fileinstall.internal.WatcherScanner.scan(WatcherScanner.java:70)[6:org.apache.felix.fileinstall:3.4.0]
> at
> org.apache.felix.fileinstall.internal.DirectoryWatcher.run(DirectoryWatcher.java:305)[6:org.apache.felix.fileinstall:3.4.0]
> {code}
> The problem looks to stem from line 83 of WatcherScanner. The "changed"
> HashSet is being modified (remove call) within the for loop that is iterating
> over it.
> Most likely, a small change of:
> {code}
> Index: WatcherScanner.java
> ===
> --- WatcherScanner.java (revision 1619096)
> +++ WatcherScanner.java (working copy)
> @@ -78,10 +78,8 @@
> if ((newChecksum == lastChecksum || reportImmediately)) {
> if (newChecksum != storedChecksum) {
> storedChecksums.put(file, newChecksum);
> -files.add(file);
> -} else {
> -changed.remove(file);
> }
> +files.add(file);
> if (reportImmediately) {
> removed.remove(file);
> }
> {code}
> will fix it, but untested at this point.
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[jira] [Commented] (FELIX-4609) Possible ConcurrentModificationException in WatcherScanner
[
https://issues.apache.org/jira/browse/FELIX-4609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14103883#comment-14103883
]
Daniel Kulp commented on FELIX-4609:
It's partially duplicated by FELIX-4532, but I think the ScannerWatcher
modifying the changed set is also a possible cause.
> Possible ConcurrentModificationException in WatcherScanner
> --
>
> Key: FELIX-4609
> URL: https://issues.apache.org/jira/browse/FELIX-4609
> Project: Felix
> Issue Type: Bug
> Components: File Install
>Affects Versions: fileinstall-3.4.0
>Reporter: Daniel Kulp
>
> In some cases at startup, I'm getting:
> {code}
> 12:02:06,941 | ERROR | OT/container/etc | ?
> ? | 6 - org.apache.felix.fileinstall - 3.4.0 | In main loop, we have serious
> trouble
> java.util.ConcurrentModificationException
> at java.util.HashMap$HashIterator.nextEntry(HashMap.java:922)[:1.7.0_67]
> at java.util.HashMap$KeyIterator.next(HashMap.java:956)[:1.7.0_67]
> at
> org.apache.felix.fileinstall.internal.WatcherScanner.scan(WatcherScanner.java:70)[6:org.apache.felix.fileinstall:3.4.0]
> at
> org.apache.felix.fileinstall.internal.DirectoryWatcher.run(DirectoryWatcher.java:305)[6:org.apache.felix.fileinstall:3.4.0]
> {code}
> The problem looks to stem from line 83 of WatcherScanner. The "changed"
> HashSet is being modified (remove call) within the for loop that is iterating
> over it.
> Most likely, a small change of:
> {code}
> Index: WatcherScanner.java
> ===
> --- WatcherScanner.java (revision 1619096)
> +++ WatcherScanner.java (working copy)
> @@ -78,10 +78,8 @@
> if ((newChecksum == lastChecksum || reportImmediately)) {
> if (newChecksum != storedChecksum) {
> storedChecksums.put(file, newChecksum);
> -files.add(file);
> -} else {
> -changed.remove(file);
> }
> +files.add(file);
> if (reportImmediately) {
> removed.remove(file);
> }
> {code}
> will fix it, but untested at this point.
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[jira] [Commented] (FELIX-4609) Possible ConcurrentModificationException in WatcherScanner
[
https://issues.apache.org/jira/browse/FELIX-4609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14103874#comment-14103874
]
Daniel Kulp commented on FELIX-4609:
Actually, the ScannerWatcher could also be adding a file to the changed set
during this iteration. The nio based Watcher could be called at pretty much
any time and then add the file to the changed set.
In addition to the above, I'd recommend changing from a HashSet to a
ConcurrentHashMap or CopyOnWriteArraySet or some other concurrent safe
implementation.
> Possible ConcurrentModificationException in WatcherScanner
> --
>
> Key: FELIX-4609
> URL: https://issues.apache.org/jira/browse/FELIX-4609
> Project: Felix
> Issue Type: Bug
> Components: File Install
>Affects Versions: fileinstall-3.4.0
>Reporter: Daniel Kulp
>
> In some cases at startup, I'm getting:
> {code}
> 12:02:06,941 | ERROR | OT/container/etc | ?
> ? | 6 - org.apache.felix.fileinstall - 3.4.0 | In main loop, we have serious
> trouble
> java.util.ConcurrentModificationException
> at java.util.HashMap$HashIterator.nextEntry(HashMap.java:922)[:1.7.0_67]
> at java.util.HashMap$KeyIterator.next(HashMap.java:956)[:1.7.0_67]
> at
> org.apache.felix.fileinstall.internal.WatcherScanner.scan(WatcherScanner.java:70)[6:org.apache.felix.fileinstall:3.4.0]
> at
> org.apache.felix.fileinstall.internal.DirectoryWatcher.run(DirectoryWatcher.java:305)[6:org.apache.felix.fileinstall:3.4.0]
> {code}
> The problem looks to stem from line 83 of WatcherScanner. The "changed"
> HashSet is being modified (remove call) within the for loop that is iterating
> over it.
> Most likely, a small change of:
> {code}
> Index: WatcherScanner.java
> ===
> --- WatcherScanner.java (revision 1619096)
> +++ WatcherScanner.java (working copy)
> @@ -78,10 +78,8 @@
> if ((newChecksum == lastChecksum || reportImmediately)) {
> if (newChecksum != storedChecksum) {
> storedChecksums.put(file, newChecksum);
> -files.add(file);
> -} else {
> -changed.remove(file);
> }
> +files.add(file);
> if (reportImmediately) {
> removed.remove(file);
> }
> {code}
> will fix it, but untested at this point.
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