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Kihwal Lee commented on MAPREDUCE-1700: --------------------------------------- Now that we have a much better way of dealing with dependency conflicts, what will be the fate of "mapreduce.job.user.classpath.first" feature? Is there any use case where this feature works but the CCL approach don't or somehow is preferred over CCL for some reason? If none, shall we deprecate it? > User supplied dependencies may conflict with MapReduce system JARs > ------------------------------------------------------------------ > > Key: MAPREDUCE-1700 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-1700 > Project: Hadoop Map/Reduce > Issue Type: Bug > Components: task > Reporter: Tom White > Assignee: Tom White > Attachments: MAPREDUCE-1700-ccl.patch, MAPREDUCE-1700-ccl.patch, > MAPREDUCE-1700.patch, MAPREDUCE-1700.patch, MAPREDUCE-1700.patch, > MAPREDUCE-1700.patch, MAPREDUCE-1700.patch, MAPREDUCE-1700.patch > > > If user code has a dependency on a version of a JAR that is different to the > one that happens to be used by Hadoop, then it may not work correctly. This > happened with user code using a different version of Avro, as reported > [here|https://issues.apache.org/jira/browse/AVRO-493?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12852081#action_12852081]. > The problem is analogous to the one that application servers have with WAR > loading. Using a specialized classloader in the Child JVM is probably the way > to solve this. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira