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Scott Carey commented on MAPREDUCE-1700: ---------------------------------------- {quote} You can always change the client framework and make it work with user code, per job, with class path ordering. There is currently always a way in both Hadoop 1 and 2 to submit a job with arbitrary dependencies, even though it might not be pretty (may require change to client framework).{quote} Without a user doing classloader gymnasitics and fancy packaging themselves, there is not always a way. A user cannot simply package a jar up and ask hadoop to execute it and expose to the user's execution environment only the public Hadoop API. > 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.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