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https://issues.apache.org/jira/browse/DERBY-4306?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mamta A. Satoor updated DERBY-4306:
-----------------------------------
Attachment: DERBY4306_checkForNullability_patch1_diff.txt
I am attaching a really simple fix as
DERBY4306_checkForNullability_patch1_diff.txt Can someone more familiar with
JMX please take a look and verify if the fix is as simple as checking for
nullability. It appears that registeredMbeans is null and hence following
results in NPE
private synchronized void unregisterMBean(final ObjectName mbeanName)
{
if (registeredMbeans.remove(mbeanName) == null)
return;
if (mbeanServer == null)
return;
jmxUnregister(mbeanName);
}
My proposed check just does following at the beginning of the method
if (registeredMbeans == null) return
So, the method will look as follows
private synchronized void unregisterMBean(final ObjectName mbeanName)
{
//Has this service been shut down?
if (registeredMbeans == null)
return;
if (registeredMbeans.remove(mbeanName) == null)
return;
if (mbeanServer == null)
return;
jmxUnregister(mbeanName);
}
I talked to Kathey about the fix and Kathey thought that there is a possibility
that registeredMbeans will be null when this method is called but she wanted me
to check with the community to see if anything thinks it is wrong to assume
that registeredMbeans can be null.
*************
Kathey's thoughts on the issue
If you shutdown the engine with shutdown=true I think the service is stopped
and mbeans unregistered at that time.If derby embedded has already been
shutdown before the network server shutdown command is issued then I think that
is when you get this JMX NPE
*************
I will go ahead and checkin the fix tomorrow after running the junit and
derbyall. If someone thinks this is the right way of fixing the problem, please
let me know.
> NullPointerException in JMXManagementService.unregisterMBean when running
> jdbcapi._Suite
> ----------------------------------------------------------------------------------------
>
> Key: DERBY-4306
> URL: https://issues.apache.org/jira/browse/DERBY-4306
> Project: Derby
> Issue Type: Bug
> Components: JMX
> Affects Versions: 10.5.2.0, 10.6.0.0
> Reporter: Tiago R. Espinha
> Attachments: DERBY4306_checkForNullability_patch1_diff.txt,
> JMX_NPE_AuthenticationTest.tar.gz, JMXNPE.tar.gz, ReproDerby4306.java
>
>
> I consistently get a NullPointerException when I run the jdbcapi suite:
> java.lang.NullPointerException
> at
> org.apache.derby.impl.services.jmx.JMXManagementService.unregisterMBean(JMXManagementService.java:286)
> at
> org.apache.derby.impl.services.jmx.JMXManagementService.unregisterMBean(JMXManagementService.java:277)
> at
> org.apache.derby.impl.drda.NetworkServerControlImpl.blockingStart(NetworkServerControlImpl.java:864)
> at sun.reflect.GeneratedMethodAccessor41.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at
> org.apache.derby.iapi.jdbc.DRDAServerStarter.run(DRDAServerStarter.java:236)
> at java.lang.Thread.run(Thread.java:619)
> I'm attaching the log folder from the jdbcapi run.
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