[Minor] Fix import order and other coding style

[Bilna]

fixed import order and other coding style

[AmplabJenkins]

Can one of the admins verify this patch?

[rxin]

Jenkins, test this please.

[SparkQA]

Test build #25304 has started for PR 3966 at commit 5e76f04.

• This patch merges cleanly.

[SparkQA]

Test build #25304 has finished for PR 3966 at commit 5e76f04.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[AmplabJenkins]

Test FAILed.
Refer to this link for build results (access rights to CI server needed):
https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder/25304/
Test FAILed.

[srowen]

I think the stance has been to avoid one-off non-functional style changes for their own sake, as it buys almost nothing and costs time to review/test/resolve merge conflicts.

If this were going to proceed, I would say you should also squash the ~20 commits here to one.

[rxin]

@srowen this one might be ok since it is limited to a smaller scope - but I agree in general it is not a good idea to do massive style changes. When we merge, the merge script does automatic squash, so that it is not a huge problem here (but still would be nice if pr owners can squash for clarity in general).

[andrewor14]

Ok, this one doesn't seem too invasive so I will go ahead and merge it in master. Thanks.