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Posted to dev@jackrabbit.apache.org by "Alexander Klimetschek (JIRA)" <ji...@apache.org> on 2009/11/02 15:26:59 UTC
[jira] Created: (JCR-2378) Avoid exceptions thrown in finalize
handler of RepositoryImpl constructor
Avoid exceptions thrown in finalize handler of RepositoryImpl constructor
-------------------------------------------------------------------------
Key: JCR-2378
URL: https://issues.apache.org/jira/browse/JCR-2378
Project: Jackrabbit Content Repository
Issue Type: Improvement
Components: jackrabbit-core
Affects Versions: 2.0-alpha11
Reporter: Alexander Klimetschek
Priority: Minor
If an exception happens during initialization of the repository, it might be overlayed by an exception thrown in the finalize handler of the RepositoryImpl constructor (see line 382 ff in [1]). The latter exception wins and the original exception is lost (if you don't have a log). This makes it hard to figure out the real problem.
This problem is actually a bit self-enforcing: if something goes wrong during startup, the code in the shutdown() method that is called is actually very prone to fail as it might not expect such a broken-startup state. In my case the overlaying NPE happened in ObservationManagerImpl.getRegisteredEventListeners, where this.dispatcher was unexpectedly null [2].
I think both places should be fixed (NPE guard in ObservationManagerImpl constructor for "dispatcher") and a try/catch block in the finalizer, just logging the exception:
} finally {
if (!succeeded) {
try {
// repository startup failed, clean up...
shutdown();
} catch (Throwable t) {
// shutdown() likely to fail now, as startup was broken...
log.error("In addition to startup fail, another problem occurred while shutting down the repository again.", e);
}
}
}
[1] http://svn.apache.org/viewvc/jackrabbit/trunk/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/RepositoryImpl.java?view=markup
[2] Overlaying exception's stacktrace:
Caused by: java.lang.NullPointerException
at org.apache.jackrabbit.core.observation.ObservationManagerImpl.getRegisteredEventListeners(ObservationManagerImpl.java:143)
at org.apache.jackrabbit.core.SessionImpl.removeRegisteredEventListeners(SessionImpl.java:1190)
at org.apache.jackrabbit.core.SessionImpl.logout(SessionImpl.java:1215)
at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.doDispose(RepositoryImpl.java:2153)
at com.day.crx.core.CRXRepositoryImpl$CRXWorkspaceInfo.doDispose(CRXRepositoryImpl.java:1095)
at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.dispose(RepositoryImpl.java:2108)
at org.apache.jackrabbit.core.RepositoryImpl.doShutdown(RepositoryImpl.java:1146)
at com.day.crx.core.CRXRepositoryImpl.doShutdown(CRXRepositoryImpl.java:845)
at org.apache.jackrabbit.core.RepositoryImpl.shutdown(RepositoryImpl.java:1098)
at org.apache.jackrabbit.core.RepositoryImpl.<init>(RepositoryImpl.java:387)
at com.day.crx.core.CRXRepositoryImpl.<init>(CRXRepositoryImpl.java:201)
at com.day.crx.core.CRXRepositoryImpl.create(CRXRepositoryImpl.java:190)
... 28 more
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[jira] Updated: (JCR-2378) Avoid exceptions thrown in finalize
handler of RepositoryImpl constructor
Posted by "Alexander Klimetschek (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/JCR-2378?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Alexander Klimetschek updated JCR-2378:
---------------------------------------
Attachment: JCR-2378.patch
Patch that both fixes the NPE in ObservationManagerImpl (throws early now) and adds the try/catch to the finalizer.
> Avoid exceptions thrown in finalize handler of RepositoryImpl constructor
> -------------------------------------------------------------------------
>
> Key: JCR-2378
> URL: https://issues.apache.org/jira/browse/JCR-2378
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: jackrabbit-core
> Affects Versions: 2.0-alpha11
> Reporter: Alexander Klimetschek
> Priority: Minor
> Attachments: JCR-2378.patch
>
>
> If an exception happens during initialization of the repository, it might be overlayed by an exception thrown in the finalize handler of the RepositoryImpl constructor (see line 382 ff in [1]). The latter exception wins and the original exception is lost (if you don't have a log). This makes it hard to figure out the real problem.
> This problem is actually a bit self-enforcing: if something goes wrong during startup, the code in the shutdown() method that is called is actually very prone to fail as it might not expect such a broken-startup state. In my case the overlaying NPE happened in ObservationManagerImpl.getRegisteredEventListeners, where this.dispatcher was unexpectedly null [2].
> I think both places should be fixed (NPE guard in ObservationManagerImpl constructor for "dispatcher") and a try/catch block in the finalizer, just logging the exception:
> } finally {
> if (!succeeded) {
> try {
> // repository startup failed, clean up...
> shutdown();
> } catch (Throwable t) {
> // shutdown() likely to fail now, as startup was broken...
> log.error("In addition to startup fail, another problem occurred while shutting down the repository again.", e);
> }
> }
> }
> [1] http://svn.apache.org/viewvc/jackrabbit/trunk/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/RepositoryImpl.java?view=markup
> [2] Overlaying exception's stacktrace:
> Caused by: java.lang.NullPointerException
> at org.apache.jackrabbit.core.observation.ObservationManagerImpl.getRegisteredEventListeners(ObservationManagerImpl.java:143)
> at org.apache.jackrabbit.core.SessionImpl.removeRegisteredEventListeners(SessionImpl.java:1190)
> at org.apache.jackrabbit.core.SessionImpl.logout(SessionImpl.java:1215)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.doDispose(RepositoryImpl.java:2153)
> at com.day.crx.core.CRXRepositoryImpl$CRXWorkspaceInfo.doDispose(CRXRepositoryImpl.java:1095)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.dispose(RepositoryImpl.java:2108)
> at org.apache.jackrabbit.core.RepositoryImpl.doShutdown(RepositoryImpl.java:1146)
> at com.day.crx.core.CRXRepositoryImpl.doShutdown(CRXRepositoryImpl.java:845)
> at org.apache.jackrabbit.core.RepositoryImpl.shutdown(RepositoryImpl.java:1098)
> at org.apache.jackrabbit.core.RepositoryImpl.<init>(RepositoryImpl.java:387)
> at com.day.crx.core.CRXRepositoryImpl.<init>(CRXRepositoryImpl.java:201)
> at com.day.crx.core.CRXRepositoryImpl.create(CRXRepositoryImpl.java:190)
> ... 28 more
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[jira] Commented: (JCR-2378) Avoid exceptions thrown in finalize
handler of RepositoryImpl constructor
Posted by "Alexander Klimetschek (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/JCR-2378?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12772546#action_12772546 ]
Alexander Klimetschek commented on JCR-2378:
--------------------------------------------
> I would prefer to see a solution to the root cause
Yes, but I think there is too much involved to capture all possible problems (easily). Therefore I think this is just good defensive programming. I'll change the wording and add "unexpected" rather than "likely to fail".
Also created a separate issue for the NPE: JCR-2380
> Avoid exceptions thrown in finalize handler of RepositoryImpl constructor
> -------------------------------------------------------------------------
>
> Key: JCR-2378
> URL: https://issues.apache.org/jira/browse/JCR-2378
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: jackrabbit-core
> Affects Versions: 2.0-alpha11
> Reporter: Alexander Klimetschek
> Assignee: Alexander Klimetschek
> Priority: Minor
> Attachments: JCR-2378.patch
>
>
> If an exception happens during initialization of the repository, it might be overlayed by an exception thrown in the finalize handler of the RepositoryImpl constructor (see line 382 ff in [1]). The latter exception wins and the original exception is lost (if you don't have a log). This makes it hard to figure out the real problem.
> This problem is actually a bit self-enforcing: if something goes wrong during startup, the code in the shutdown() method that is called is actually very prone to fail as it might not expect such a broken-startup state. In my case the overlaying NPE happened in ObservationManagerImpl.getRegisteredEventListeners, where this.dispatcher was unexpectedly null [2].
> I think both places should be fixed (NPE guard in ObservationManagerImpl constructor for "dispatcher") and a try/catch block in the finalizer, just logging the exception:
> } finally {
> if (!succeeded) {
> try {
> // repository startup failed, clean up...
> shutdown();
> } catch (Throwable t) {
> // shutdown() likely to fail now, as startup was broken...
> log.error("In addition to startup fail, another problem occurred while shutting down the repository again.", e);
> }
> }
> }
> [1] http://svn.apache.org/viewvc/jackrabbit/trunk/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/RepositoryImpl.java?view=markup
> [2] Overlaying exception's stacktrace:
> Caused by: java.lang.NullPointerException
> at org.apache.jackrabbit.core.observation.ObservationManagerImpl.getRegisteredEventListeners(ObservationManagerImpl.java:143)
> at org.apache.jackrabbit.core.SessionImpl.removeRegisteredEventListeners(SessionImpl.java:1190)
> at org.apache.jackrabbit.core.SessionImpl.logout(SessionImpl.java:1215)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.doDispose(RepositoryImpl.java:2153)
> at com.day.crx.core.CRXRepositoryImpl$CRXWorkspaceInfo.doDispose(CRXRepositoryImpl.java:1095)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.dispose(RepositoryImpl.java:2108)
> at org.apache.jackrabbit.core.RepositoryImpl.doShutdown(RepositoryImpl.java:1146)
> at com.day.crx.core.CRXRepositoryImpl.doShutdown(CRXRepositoryImpl.java:845)
> at org.apache.jackrabbit.core.RepositoryImpl.shutdown(RepositoryImpl.java:1098)
> at org.apache.jackrabbit.core.RepositoryImpl.<init>(RepositoryImpl.java:387)
> at com.day.crx.core.CRXRepositoryImpl.<init>(CRXRepositoryImpl.java:201)
> at com.day.crx.core.CRXRepositoryImpl.create(CRXRepositoryImpl.java:190)
> ... 28 more
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[jira] Updated: (JCR-2378) Avoid exceptions thrown in finalize
handler of RepositoryImpl constructor
Posted by "Alexander Klimetschek (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/JCR-2378?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Alexander Klimetschek updated JCR-2378:
---------------------------------------
Resolution: Fixed
Fix Version/s: 2.0.0
Status: Resolved (was: Patch Available)
Added the finalizer change in revision 831932.
> Avoid exceptions thrown in finalize handler of RepositoryImpl constructor
> -------------------------------------------------------------------------
>
> Key: JCR-2378
> URL: https://issues.apache.org/jira/browse/JCR-2378
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: jackrabbit-core
> Affects Versions: 2.0-alpha11
> Reporter: Alexander Klimetschek
> Assignee: Alexander Klimetschek
> Priority: Minor
> Fix For: 2.0.0
>
> Attachments: JCR-2378.patch
>
>
> If an exception happens during initialization of the repository, it might be overlayed by an exception thrown in the finalize handler of the RepositoryImpl constructor (see line 382 ff in [1]). The latter exception wins and the original exception is lost (if you don't have a log). This makes it hard to figure out the real problem.
> This problem is actually a bit self-enforcing: if something goes wrong during startup, the code in the shutdown() method that is called is actually very prone to fail as it might not expect such a broken-startup state. In my case the overlaying NPE happened in ObservationManagerImpl.getRegisteredEventListeners, where this.dispatcher was unexpectedly null [2].
> I think both places should be fixed (NPE guard in ObservationManagerImpl constructor for "dispatcher") and a try/catch block in the finalizer, just logging the exception:
> } finally {
> if (!succeeded) {
> try {
> // repository startup failed, clean up...
> shutdown();
> } catch (Throwable t) {
> // shutdown() likely to fail now, as startup was broken...
> log.error("In addition to startup fail, another problem occurred while shutting down the repository again.", e);
> }
> }
> }
> [1] http://svn.apache.org/viewvc/jackrabbit/trunk/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/RepositoryImpl.java?view=markup
> [2] Overlaying exception's stacktrace:
> Caused by: java.lang.NullPointerException
> at org.apache.jackrabbit.core.observation.ObservationManagerImpl.getRegisteredEventListeners(ObservationManagerImpl.java:143)
> at org.apache.jackrabbit.core.SessionImpl.removeRegisteredEventListeners(SessionImpl.java:1190)
> at org.apache.jackrabbit.core.SessionImpl.logout(SessionImpl.java:1215)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.doDispose(RepositoryImpl.java:2153)
> at com.day.crx.core.CRXRepositoryImpl$CRXWorkspaceInfo.doDispose(CRXRepositoryImpl.java:1095)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.dispose(RepositoryImpl.java:2108)
> at org.apache.jackrabbit.core.RepositoryImpl.doShutdown(RepositoryImpl.java:1146)
> at com.day.crx.core.CRXRepositoryImpl.doShutdown(CRXRepositoryImpl.java:845)
> at org.apache.jackrabbit.core.RepositoryImpl.shutdown(RepositoryImpl.java:1098)
> at org.apache.jackrabbit.core.RepositoryImpl.<init>(RepositoryImpl.java:387)
> at com.day.crx.core.CRXRepositoryImpl.<init>(CRXRepositoryImpl.java:201)
> at com.day.crx.core.CRXRepositoryImpl.create(CRXRepositoryImpl.java:190)
> ... 28 more
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[jira] Updated: (JCR-2378) Avoid exceptions thrown in finalize
handler of RepositoryImpl constructor
Posted by "Alexander Klimetschek (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/JCR-2378?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Alexander Klimetschek updated JCR-2378:
---------------------------------------
Assignee: Alexander Klimetschek
Status: Patch Available (was: Open)
Patch available.
> Avoid exceptions thrown in finalize handler of RepositoryImpl constructor
> -------------------------------------------------------------------------
>
> Key: JCR-2378
> URL: https://issues.apache.org/jira/browse/JCR-2378
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: jackrabbit-core
> Affects Versions: 2.0-alpha11
> Reporter: Alexander Klimetschek
> Assignee: Alexander Klimetschek
> Priority: Minor
> Attachments: JCR-2378.patch
>
>
> If an exception happens during initialization of the repository, it might be overlayed by an exception thrown in the finalize handler of the RepositoryImpl constructor (see line 382 ff in [1]). The latter exception wins and the original exception is lost (if you don't have a log). This makes it hard to figure out the real problem.
> This problem is actually a bit self-enforcing: if something goes wrong during startup, the code in the shutdown() method that is called is actually very prone to fail as it might not expect such a broken-startup state. In my case the overlaying NPE happened in ObservationManagerImpl.getRegisteredEventListeners, where this.dispatcher was unexpectedly null [2].
> I think both places should be fixed (NPE guard in ObservationManagerImpl constructor for "dispatcher") and a try/catch block in the finalizer, just logging the exception:
> } finally {
> if (!succeeded) {
> try {
> // repository startup failed, clean up...
> shutdown();
> } catch (Throwable t) {
> // shutdown() likely to fail now, as startup was broken...
> log.error("In addition to startup fail, another problem occurred while shutting down the repository again.", e);
> }
> }
> }
> [1] http://svn.apache.org/viewvc/jackrabbit/trunk/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/RepositoryImpl.java?view=markup
> [2] Overlaying exception's stacktrace:
> Caused by: java.lang.NullPointerException
> at org.apache.jackrabbit.core.observation.ObservationManagerImpl.getRegisteredEventListeners(ObservationManagerImpl.java:143)
> at org.apache.jackrabbit.core.SessionImpl.removeRegisteredEventListeners(SessionImpl.java:1190)
> at org.apache.jackrabbit.core.SessionImpl.logout(SessionImpl.java:1215)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.doDispose(RepositoryImpl.java:2153)
> at com.day.crx.core.CRXRepositoryImpl$CRXWorkspaceInfo.doDispose(CRXRepositoryImpl.java:1095)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.dispose(RepositoryImpl.java:2108)
> at org.apache.jackrabbit.core.RepositoryImpl.doShutdown(RepositoryImpl.java:1146)
> at com.day.crx.core.CRXRepositoryImpl.doShutdown(CRXRepositoryImpl.java:845)
> at org.apache.jackrabbit.core.RepositoryImpl.shutdown(RepositoryImpl.java:1098)
> at org.apache.jackrabbit.core.RepositoryImpl.<init>(RepositoryImpl.java:387)
> at com.day.crx.core.CRXRepositoryImpl.<init>(CRXRepositoryImpl.java:201)
> at com.day.crx.core.CRXRepositoryImpl.create(CRXRepositoryImpl.java:190)
> ... 28 more
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[jira] Commented: (JCR-2378) Avoid exceptions thrown in finalize
handler of RepositoryImpl constructor
Posted by "Jukka Zitting (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/JCR-2378?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12772539#action_12772539 ]
Jukka Zitting commented on JCR-2378:
------------------------------------
+0 I would prefer to see a solution to the root cause (shutdown not working properly when repository startup fails) instead of a workaround, but until such a solution is available I think doing something like this is a good alternative.
> Avoid exceptions thrown in finalize handler of RepositoryImpl constructor
> -------------------------------------------------------------------------
>
> Key: JCR-2378
> URL: https://issues.apache.org/jira/browse/JCR-2378
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: jackrabbit-core
> Affects Versions: 2.0-alpha11
> Reporter: Alexander Klimetschek
> Assignee: Alexander Klimetschek
> Priority: Minor
> Attachments: JCR-2378.patch
>
>
> If an exception happens during initialization of the repository, it might be overlayed by an exception thrown in the finalize handler of the RepositoryImpl constructor (see line 382 ff in [1]). The latter exception wins and the original exception is lost (if you don't have a log). This makes it hard to figure out the real problem.
> This problem is actually a bit self-enforcing: if something goes wrong during startup, the code in the shutdown() method that is called is actually very prone to fail as it might not expect such a broken-startup state. In my case the overlaying NPE happened in ObservationManagerImpl.getRegisteredEventListeners, where this.dispatcher was unexpectedly null [2].
> I think both places should be fixed (NPE guard in ObservationManagerImpl constructor for "dispatcher") and a try/catch block in the finalizer, just logging the exception:
> } finally {
> if (!succeeded) {
> try {
> // repository startup failed, clean up...
> shutdown();
> } catch (Throwable t) {
> // shutdown() likely to fail now, as startup was broken...
> log.error("In addition to startup fail, another problem occurred while shutting down the repository again.", e);
> }
> }
> }
> [1] http://svn.apache.org/viewvc/jackrabbit/trunk/jackrabbit-core/src/main/java/org/apache/jackrabbit/core/RepositoryImpl.java?view=markup
> [2] Overlaying exception's stacktrace:
> Caused by: java.lang.NullPointerException
> at org.apache.jackrabbit.core.observation.ObservationManagerImpl.getRegisteredEventListeners(ObservationManagerImpl.java:143)
> at org.apache.jackrabbit.core.SessionImpl.removeRegisteredEventListeners(SessionImpl.java:1190)
> at org.apache.jackrabbit.core.SessionImpl.logout(SessionImpl.java:1215)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.doDispose(RepositoryImpl.java:2153)
> at com.day.crx.core.CRXRepositoryImpl$CRXWorkspaceInfo.doDispose(CRXRepositoryImpl.java:1095)
> at org.apache.jackrabbit.core.RepositoryImpl$WorkspaceInfo.dispose(RepositoryImpl.java:2108)
> at org.apache.jackrabbit.core.RepositoryImpl.doShutdown(RepositoryImpl.java:1146)
> at com.day.crx.core.CRXRepositoryImpl.doShutdown(CRXRepositoryImpl.java:845)
> at org.apache.jackrabbit.core.RepositoryImpl.shutdown(RepositoryImpl.java:1098)
> at org.apache.jackrabbit.core.RepositoryImpl.<init>(RepositoryImpl.java:387)
> at com.day.crx.core.CRXRepositoryImpl.<init>(CRXRepositoryImpl.java:201)
> at com.day.crx.core.CRXRepositoryImpl.create(CRXRepositoryImpl.java:190)
> ... 28 more
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