HDDS-2102. HddsVolumeChecker should use java optional in place of Guava optional. Contributed by Mukul Kumar Singh.

[mukul1987]

HddsVolumeChecker should use java optional in place of Guava optional as Guava Optional is marked as unstable.

[bharatviswa504]

+1 LGTM, pending CI.
Thank You @mukul1987 for the fix.

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Comment
0	reexec	100	Docker mode activated.
		_ Prechecks _
+1	dupname	0	No case conflicting files found.
+1	@author	0	The patch does not contain any @author tags.
+1	test4tests	0	The patch appears to include 1 new or modified test files.
		_ trunk Compile Tests _
+1	mvninstall	691	trunk passed
+1	compile	388	trunk passed
+1	checkstyle	74	trunk passed
+1	mvnsite	0	trunk passed
+1	shadedclient	979	branch has no errors when building and testing our client artifacts.
+1	javadoc	185	trunk passed
0	spotbugs	453	Used deprecated FindBugs config; considering switching to SpotBugs.
+1	findbugs	688	trunk passed
		_ Patch Compile Tests _
+1	mvninstall	555	the patch passed
+1	compile	409	the patch passed
+1	javac	409	the patch passed
+1	checkstyle	80	the patch passed
+1	mvnsite	0	the patch passed
+1	whitespace	0	The patch has no whitespace issues.
+1	shadedclient	725	patch has no errors when building and testing our client artifacts.
+1	javadoc	183	the patch passed
+1	findbugs	768	the patch passed
		_ Other Tests _
-1	unit	313	hadoop-hdds in the patch failed.
-1	unit	289	hadoop-ozone in the patch failed.
+1	asflicense	42	The patch does not generate ASF License warnings.
		6642

Reason	Tests
Failed junit tests	hadoop.hdds.scm.block.TestBlockManager
	hadoop.ozone.om.ratis.TestOzoneManagerRatisServer

Subsystem	Report/Notes
Docker	Client=18.09.7 Server=18.09.7 base: https://builds.apache.org/job/hadoop-multibranch/job/PR-1416/1/artifact/out/Dockerfile
GITHUB PR	#1416
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient findbugs checkstyle
uname	Linux 626c82f6d9c2 4.15.0-58-generic #64-Ubuntu SMP Tue Aug 6 11:12:41 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	personality/hadoop.sh
git revision	trunk / 469165e
Default Java	1.8.0_222
unit	https://builds.apache.org/job/hadoop-multibranch/job/PR-1416/1/artifact/out/patch-unit-hadoop-hdds.txt
unit	https://builds.apache.org/job/hadoop-multibranch/job/PR-1416/1/artifact/out/patch-unit-hadoop-ozone.txt
Test Results	https://builds.apache.org/job/hadoop-multibranch/job/PR-1416/1/testReport/
Max. process+thread count	1325 (vs. ulimit of 5500)
modules	C: hadoop-hdds/container-service U: hadoop-hdds/container-service
Console output	https://builds.apache.org/job/hadoop-multibranch/job/PR-1416/1/console
versions	git=2.7.4 maven=3.3.9 findbugs=3.1.0-RC1
Powered by	Apache Yetus 0.10.0 http://yetus.apache.org

This message was automatically generated.

[bharatviswa504]

Thank You @mukul1987 for the contribution.
I have committed this to the trunk.