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Subject: Re: Review Request 25172: ConcurrentModificationException in Resource
 Comparator
From: "Tom Beerbower" <tbeerbower@hortonworks.com>
To: "John Speidel" <jspeidel@hortonworks.com>,
 "Sid Wagle" <swagle@hortonworks.com>
Cc: "Ambari" <dev@ambari.apache.org>,
 "Tom Beerbower" <tbeerbower@hortonworks.com>
Date: Fri, 29 Aug 2014 10:55:38 -0000
Message-ID: <20140829105538.17468.84554@reviews.apache.org>
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Reply-To: "Tom Beerbower" <tbeerbower@hortonworks.com>

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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/25172/
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(Updated Aug. 29, 2014, 10:55 a.m.)


Review request for Ambari, John Speidel and Sid Wagle.


Changes
-------

Update patch.


Bugs: ambari-7067
    https://issues.apache.org/jira/browse/ambari-7067


Repository: ambari


Description
-------

It looks like that when the JMX property provider times out, we just log the message and bail out of the provider. The query continues but so do the threads trying to acquire the JMX metrics. So the Comparator used at the end of the query gets a ConcurrentModificationException because another thread is still adding properties to the resource.

{code}
java.util.ConcurrentModificationException
	at java.util.TreeMap$PrivateEntryIterator.nextEntry(TreeMap.java:1100)
	at java.util.TreeMap$EntryIterator.next(TreeMap.java:1136)
	at java.util.TreeMap$EntryIterator.next(TreeMap.java:1131)
	at java.util.AbstractMap.toString(AbstractMap.java:485)
	at java.lang.String.valueOf(String.java:2826)
	at java.lang.StringBuilder.append(StringBuilder.java:115)
	at java.util.AbstractMap.toString(AbstractMap.java:490)
	at java.lang.String.valueOf(String.java:2826)
	at java.lang.StringBuilder.append(StringBuilder.java:115)
	at org.apache.ambari.server.controller.internal.ResourceImpl.toString(ResourceImpl.java:143)
	at org.apache.ambari.server.controller.internal.ClusterControllerImpl$ResourceComparator.compare(ClusterControllerImpl.java:828)
	at org.apache.ambari.server.controller.internal.ClusterControllerImpl$ResourceComparator.compare(ClusterControllerImpl.java:773)
	at org.apache.ambari.server.controller.internal.ClusterControllerImplTest.testComparatorConcurrentModification(ClusterControllerImplTest.java:857)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:76)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:195)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:63)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

{code}


Diffs (updated)
-----

  ambari-server/src/main/java/org/apache/ambari/server/controller/jmx/JMXPropertyProvider.java b5a5059 
  ambari-server/src/test/java/org/apache/ambari/server/controller/jmx/JMXPropertyProviderTest.java b4c3c6a 

Diff: https://reviews.apache.org/r/25172/diff/


Testing
-------

Added new unit test.  All existing tests pass.


Thanks,

Tom Beerbower


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