MAPREDUCE-7377. Remove unused imports in MapReduce project

[hotcodemacha]

Description of PR

Remove unused Imports in Hadoop MAP/REDUCE project

• JIRA: MAPREDUCE-7377

• Does the title or this PR starts with the corresponding JIRA issue id (e.g. 'HADOOP-17799. Your PR title ...')?

[slfan1989]

Hi，@ashutoshcipher, I found unused import in yarn router moudle and yarn server moudle,
PR-4276 has been submitted, please do not submit again, Thanks for contributing to the code.

[hotcodemacha]

@slfan1989. Thanks for your comment. My PR is different from yours. I am checking in complete Hadoop MAP/REDUCE project and not in yarn router module and yarn server module in this PR.

Also I have created a separate JIRA YARN-11142 to check unused imports in complete Hadoop YARN project. When I will raise the PR, I will make sure that I am adding the new changes and not that are already done in you PR #4276

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 56s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 1s		No case conflicting files found.
+0 🆗	codespell	0m 1s		codespell was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 21 new or modified test files.
			_ trunk Compile Tests _
+0 🆗	mvndep	16m 30s		Maven dependency ordering for branch
+1 💚	mvninstall	28m 49s		trunk passed
+1 💚	compile	3m 4s		trunk passed with JDK Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1
+1 💚	compile	2m 35s		trunk passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	checkstyle	1m 23s		trunk passed
+1 💚	mvnsite	5m 10s		trunk passed
+1 💚	javadoc	4m 26s		trunk passed with JDK Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1
+1 💚	javadoc	4m 4s		trunk passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	spotbugs	7m 41s		trunk passed
+1 💚	shadedclient	22m 47s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+0 🆗	mvndep	0m 23s		Maven dependency ordering for patch
+1 💚	mvninstall	3m 36s		the patch passed
+1 💚	compile	2m 48s		the patch passed with JDK Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1
-1 ❌	javac	2m 48s	/results-compile-javac-hadoop-mapreduce-project-jdkPrivateBuild-11.0.15+10-Ubuntu-0ubuntu0.20.04.1.txt	hadoop-mapreduce-project-jdkPrivateBuild-11.0.15+10-Ubuntu-0ubuntu0.20.04.1 with JDK Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1 generated 2 new + 288 unchanged - 2 fixed = 290 total (was 290)
+1 💚	compile	2m 21s		the patch passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
-1 ❌	javac	2m 21s	/results-compile-javac-hadoop-mapreduce-project-jdkPrivateBuild-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07.txt	hadoop-mapreduce-project-jdkPrivateBuild-1.8.0_312-8u312-b07-0ubuntu120.04-b07 with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu120.04-b07 generated 2 new + 274 unchanged - 2 fixed = 276 total (was 276)
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	1m 6s		hadoop-mapreduce-project: The patch generated 0 new + 711 unchanged - 132 fixed = 711 total (was 843)
+1 💚	mvnsite	3m 50s		the patch passed
+1 💚	javadoc	3m 2s		the patch passed with JDK Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1
+1 💚	javadoc	2m 50s		the patch passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	spotbugs	7m 31s		the patch passed
+1 💚	shadedclient	22m 33s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	6m 23s		hadoop-mapreduce-client-core in the patch passed.
-1 ❌	unit	1m 5s	/patch-unit-hadoop-mapreduce-project_hadoop-mapreduce-client_hadoop-mapreduce-client-common.txt	hadoop-mapreduce-client-common in the patch passed.
+1 💚	unit	8m 30s		hadoop-mapreduce-client-app in the patch passed.
+1 💚	unit	5m 22s		hadoop-mapreduce-client-hs in the patch passed.
+1 💚	unit	133m 32s		hadoop-mapreduce-client-jobclient in the patch passed.
+1 💚	unit	2m 57s		hadoop-mapreduce-client-nativetask in the patch passed.
+1 💚	unit	0m 57s		hadoop-mapreduce-examples in the patch passed.
+1 💚	asflicense	0m 48s		The patch does not generate ASF License warnings.
		310m 12s

Reason	Tests
Failed junit tests	hadoop.mapred.TestLocalDistributedCacheManager

Subsystem	Report/Notes
Docker	ClientAPI=1.41 ServerAPI=1.41 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4299/1/artifact/out/Dockerfile
GITHUB PR	#4299
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell
uname	Linux 9173bc9c3606 4.15.0-175-generic #184-Ubuntu SMP Thu Mar 24 17:48:36 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / 3560f6b
Default Java	Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4299/1/testReport/
Max. process+thread count	1198 (vs. ulimit of 5500)
modules	C: hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-nativetask hadoop-mapreduce-project/hadoop-mapreduce-examples U: hadoop-mapreduce-project
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4299/1/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
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[hotcodemacha]

@aajisaka @ayushtkn @steveloughran , Can you please review this? Thanks.

[aajisaka]

LGTM

[aajisaka]

hadoop-mapreduce-project: The patch generated 0 new + 711 unchanged - 132 fixed = 711 total (was 843)

The number of Checkstyle warnings are greatly reduced. Thank you.

[aajisaka]

TestLocalDistributedCacheManager is failing but is not related to the patch. Filed MAPREDUCE-7380 to fix the test failure.