HADOOP-19932. Prune obsolete classes in org.apache.hadoop.io.serializer

[steveloughran]

Cull

• JavaComparator
• JavaSerialization
• DeserializerComparator

How was this patch tested?

Updated tests

For code changes:

• Does the title or this PR starts with the corresponding JIRA issue id (e.g. 'HADOOP-17799. Your PR title ...')?
• Object storage: have the integration tests been executed and the endpoint declared according to the connector-specific documentation?
• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?
• If applicable, have you updated the LICENSE, LICENSE-binary, NOTICE-binary files?

AI Tooling

If an AI tool was used:

• The PR includes the phrase "Contains content generated by "
  where is the name of the AI tool used.
• My use of AI contributions follows the ASF legal policy
  https://www.apache.org/legal/generative-tooling.html

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	19m 29s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 1s		codespell was not available.
+0 🆗	detsecrets	0m 1s		detect-secrets was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 9 new or modified test files.
			_ trunk Compile Tests _
+0 🆗	mvndep	1m 58s		Maven dependency ordering for branch
+1 💚	mvninstall	51m 14s		trunk passed
+1 💚	compile	18m 5s		trunk passed with JDK Ubuntu-21.0.11+10-1-24.04.2-Ubuntu
+1 💚	compile	18m 27s		trunk passed with JDK Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
+1 💚	checkstyle	5m 55s		trunk passed
+1 💚	mvnsite	2m 58s		trunk passed
+1 💚	javadoc	2m 11s		trunk passed with JDK Ubuntu-21.0.11+10-1-24.04.2-Ubuntu
+1 💚	javadoc	2m 7s		trunk passed with JDK Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
+1 💚	spotbugs	4m 25s		trunk passed
+1 💚	shadedclient	34m 16s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+0 🆗	mvndep	0m 30s		Maven dependency ordering for patch
+1 💚	mvninstall	1m 49s		the patch passed
+1 💚	compile	17m 13s		the patch passed with JDK Ubuntu-21.0.11+10-1-24.04.2-Ubuntu
+1 💚	javac	17m 13s		the patch passed
+1 💚	compile	18m 28s		the patch passed with JDK Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
+1 💚	javac	18m 28s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
-0 ⚠️	checkstyle	5m 51s	/results-checkstyle-root.txt	root: The patch generated 2 new + 137 unchanged - 69 fixed = 139 total (was 206)
+1 💚	mvnsite	2m 58s		the patch passed
+1 💚	javadoc	2m 6s		the patch passed with JDK Ubuntu-21.0.11+10-1-24.04.2-Ubuntu
+1 💚	javadoc	2m 5s		the patch passed with JDK Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
+1 💚	spotbugs	4m 47s		the patch passed
+1 💚	shadedclient	35m 54s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
-1 ❌	unit	23m 56s	/patch-unit-hadoop-common-project_hadoop-common.txt	hadoop-common in the patch passed.
+1 💚	unit	109m 49s		hadoop-mapreduce-client-jobclient in the patch passed.
+1 💚	asflicense	1m 20s		The patch does not generate ASF License warnings.
		396m 7s

Reason	Tests
Failed junit tests	hadoop.http.TestSSLHttpServerMTLS

Subsystem	Report/Notes
Docker	ClientAPI=1.55 ServerAPI=1.55 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8585/1/artifact/out/Dockerfile
GITHUB PR	#8585
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell detsecrets
uname	Linux 508874e48e33 5.15.0-185-generic #195-Ubuntu SMP Fri Jun 19 17:11:50 UTC 2026 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / 4e16553
Default Java	Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
Multi-JDK versions	/usr/lib/jvm/java-21-openjdk-amd64:Ubuntu-21.0.11+10-1-24.04.2-Ubuntu /usr/lib/jvm/java-17-openjdk-amd64:Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8585/1/testReport/
Max. process+thread count	3146 (vs. ulimit of 10000)
modules	C: hadoop-common-project/hadoop-common hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient U: .
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8585/1/console
versions	git=2.43.0 maven=3.9.15 spotbugs=4.9.7
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[hadoop-yetus]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 54s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 1s		codespell was not available.
+0 🆗	detsecrets	0m 1s		detect-secrets was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 9 new or modified test files.
			_ trunk Compile Tests _
+0 🆗	mvndep	2m 5s		Maven dependency ordering for branch
+1 💚	mvninstall	50m 50s		trunk passed
+1 💚	compile	17m 52s		trunk passed with JDK Ubuntu-21.0.11+10-1-24.04.2-Ubuntu
+1 💚	compile	18m 24s		trunk passed with JDK Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
+1 💚	checkstyle	5m 55s		trunk passed
+1 💚	mvnsite	2m 55s		trunk passed
+1 💚	javadoc	2m 11s		trunk passed with JDK Ubuntu-21.0.11+10-1-24.04.2-Ubuntu
+1 💚	javadoc	2m 7s		trunk passed with JDK Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
+1 💚	spotbugs	4m 23s		trunk passed
+1 💚	shadedclient	35m 23s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+0 🆗	mvndep	0m 30s		Maven dependency ordering for patch
+1 💚	mvninstall	1m 49s		the patch passed
+1 💚	compile	17m 22s		the patch passed with JDK Ubuntu-21.0.11+10-1-24.04.2-Ubuntu
+1 💚	javac	17m 22s		the patch passed
+1 💚	compile	18m 35s		the patch passed with JDK Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
+1 💚	javac	18m 35s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	5m 58s		root: The patch generated 0 new + 136 unchanged - 70 fixed = 136 total (was 206)
+1 💚	mvnsite	2m 58s		the patch passed
+1 💚	javadoc	2m 6s		the patch passed with JDK Ubuntu-21.0.11+10-1-24.04.2-Ubuntu
+1 💚	javadoc	2m 6s		the patch passed with JDK Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
+1 💚	spotbugs	4m 47s		the patch passed
+1 💚	shadedclient	35m 4s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	23m 53s		hadoop-common in the patch passed.
+1 💚	unit	108m 54s		hadoop-mapreduce-client-jobclient in the patch passed.
+1 💚	asflicense	1m 17s		The patch does not generate ASF License warnings.
		376m 15s

Subsystem	Report/Notes
Docker	ClientAPI=1.55 ServerAPI=1.55 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8585/2/artifact/out/Dockerfile
GITHUB PR	#8585
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell detsecrets
uname	Linux 3df776492d8f 5.15.0-185-generic #195-Ubuntu SMP Fri Jun 19 17:11:50 UTC 2026 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / b8b3c6f
Default Java	Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
Multi-JDK versions	/usr/lib/jvm/java-21-openjdk-amd64:Ubuntu-21.0.11+10-1-24.04.2-Ubuntu /usr/lib/jvm/java-17-openjdk-amd64:Ubuntu-17.0.19+10-1-24.04.2-Ubuntu
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8585/2/testReport/
Max. process+thread count	2146 (vs. ulimit of 10000)
modules	C: hadoop-common-project/hadoop-common hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient U: .
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8585/2/console
versions	git=2.43.0 maven=3.9.15 spotbugs=4.9.7
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This message was automatically generated.