[Mc4j-development] [ mc4j-Bugs-914838 ] MBean displayed duplicate

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Bugs item #914838, was opened at 2004-03-12 04:02
Message generated for change (Settings changed) made by ghinkl
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Category: MBeans
Group: MC4J 1.2b4
>Status: Pending
Resolution: None
Priority: 7
Submitted By: Christian Schweer (holbitlan)
>Assigned to: Greg Hinkle (ghinkl)
Summary: MBean displayed duplicate

Initial Comment:

When I connect to a JSR160 agent with mc4j 1.2b4, some
mbean are displayed duplicate.
E.g. I deployed one (!) HelloWorld MBean and the bean
is shown twice in mc4j.

If I disconnect from the agent and reconnect again, the
number of displayed mbean is correct!

Steps to reproduce:
1. startup JSR160-agent (I'm using mx4j2.0beta1)
2. deploy 2 MBeans at startup
3. start a new (!) mc4j and connect to mx4j

Expected result:
2 different beans are shown under my domain

Actual result:
3 beans are shown (1 bean is shown twice).
Disconnect from mx4j and reconnect without exiting mc4j
-> the expected result is reached.


Sometimes even my domain is doubled... but I can't
reproduce this reliably

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>Comment By: Greg Hinkle (ghinkl)
Date: 2004-05-25 22:00

Message:
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The patch has been incorporated. Thanks Christian!

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Comment By: Christian Schweer (holbitlan)
Date: 2004-05-14 07:47

Message:
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A classic race condition when the node tree is created:
Both threads "Module-Actions" and "Mc4j connection Thread"
run into the method ConnectionNode.loadConnectionNodeChildren()

Unfortunately the test whether a node is already added and
the add itself is NOT synchronized. So some nodes are
indeterministic added twice.

The provided file adds necessary synchronized blocks and
additionally I changed the method browseToNode(ObjectName)
to use getMBeanNode() instead of doing the same with own code.

Bye,
Christian


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