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https://issues.apache.org/jira/browse/HADOOP-10893?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14105724#comment-14105724
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Sangjin Lee commented on HADOOP-10893:
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The comments in hadoop-env.sh in the trunk patch are found in hadoop-config.sh
in the branch-2 patch. It appears that the existing comments pre-HADOOP-9902 in
hadoop-config.sh were replaced by (shorter) comments in hadoop-env.sh.
Hadoop-env.sh did not have comments on things like HADOOP_USER_CLASSPATH_FIRST
prior to HADOOP-9902. Following the movement, I basically moved the new
comments from hadoop-config.sh to hadoop-env.sh. If we were to move those
comments to hadoop-env.sh in branch-2, then I think we'd need to move other
existing comments similarly, or the new comments would look out of place.
Thoughts?
Also, prior to HADOOP-9902, hadoop-config.cmd did not have the mirroring
comments for the environment variables. That kind of felt awkward but again I
felt that either we recreate the same comments for all environment variables or
none. Now that has been corrected with HADOOP-9902, I decided to add the same
comments to hadoop.cmd in the trunk, thus the discrepancy between branch-2 and
trunk.
Let me know what you think about these two... Thanks!
> isolated classloader on the client side
> ---------------------------------------
>
> Key: HADOOP-10893
> URL: https://issues.apache.org/jira/browse/HADOOP-10893
> Project: Hadoop Common
> Issue Type: New Feature
> Components: util
> Affects Versions: 2.4.0
> Reporter: Sangjin Lee
> Assignee: Sangjin Lee
> Attachments: HADOOP-10893-branch-2.patch,
> HADOOP-10893-branch-2.patch, HADOOP-10893.patch, HADOOP-10893.patch,
> HADOOP-10893.patch, HADOOP-10893.patch, HADOOP-10893.patch,
> HADOOP-10893.patch, HADOOP-10893.patch, classloader-test.tar.gz
>
>
> We have the job classloader on the mapreduce tasks that run on the cluster.
> It has a benefit of being able to isolate class space for user code and avoid
> version clashes.
> Although it occurs less often, version clashes do occur on the client JVM. It
> would be good to introduce an isolated classloader on the client side as well
> to address this. A natural point to introduce this may be through RunJar, as
> that's how most of hadoop jobs are run.
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