NullpointerException in SynonymSetIndexCreationBundleActivator when restarting server

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: Master
• Fix Version/s: 7.2.10 DXP FP5, 7.2.10.2 DXP SP2, 7.2.X, 7.3.10 DXP GA1, Master
• Component/s: Search Infrastructure
• Labels:
  • QA-AUTOMATION
  • backend_test
  • liferay-dxp-72-sp2
  • liferay-fixpack-dxp-5-7210
  • qa-a
• Branch Version/s:
  7.2.x
• Backported to Branch:
  Committed
• Fix Priority: 4
• Epic Link: Search Tuning: Synonyms (Phase 2)
• Sprint: Search|S03 Sprint 10 |1.6-1.24
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/83263
• Bug Type: Regression Bug
• QA Test Name:
  • bundle-blacklist-restart-jdk8/0
  • lpkg-override-jdk8/0
  • lpkg-persistence-jdk8/0
  • lpkg-startup-jdk8/0
  • release-osgi-state-exploded-test-jdk8/0
  • release-osgi-state-lpkg-change-directory-test-jdk8/0
  • release-osgi-state-lpkg-test-jdk8/0
• QA Test Score: 35

Steps to reproduce:

1. Shut down Portal server
2. Restart Portal server

Result: Following startup errors appears in the console:

 [junit] 12:59:12,443 ERROR [main][SynonymSetIndexCreationBundleActivator:93] bundle com.liferay.portal.search.tuning.synonyms.web:2.0.0 (1259)[com.liferay.portal.search.tuning.synonyms.web.internal.index.creation.activator.SynonymSetIndexCreationBundleActivator(6029)] : The activate method has thrown an exception 
    [junit] java.lang.NullPointerException
    [junit] 	at org.elasticsearch.action.ActionRequestBuilder.execute(ActionRequestBuilder.java:46)
    [junit] 	at org.elasticsearch.action.ActionRequestBuilder.get(ActionRequestBuilder.java:53)
    [junit] 	at com.liferay.portal.search.elasticsearch6.internal.search.engine.adapter.index.IndicesExistsIndexRequestExecutorImpl.execute(IndicesExistsIndexRequestExecutorImpl.java:43)
    [junit] 	at com.liferay.portal.search.elasticsearch6.internal.search.engine.adapter.index.ElasticsearchIndexRequestExecutor.executeIndexRequest(ElasticsearchIndexRequestExecutor.java:118)
    [junit] 	at com.liferay.portal.search.engine.adapter.index.IndicesExistsIndexRequest.accept(IndicesExistsIndexRequest.java:34)
    [junit] 	at com.liferay.portal.search.engine.adapter.index.IndicesExistsIndexRequest.accept(IndicesExistsIndexRequest.java:22)
    [junit] 	at com.liferay.portal.search.elasticsearch6.internal.search.engine.adapter.ElasticsearchSearchEngineAdapterImpl.execute(ElasticsearchSearchEngineAdapterImpl.java:78)
    [junit] 	at com.liferay.portal.search.tuning.synonyms.web.internal.index.SynonymSetIndexCreatorImpl.isExists(SynonymSetIndexCreatorImpl.java:58)
    [junit] 	at com.liferay.portal.search.tuning.synonyms.web.internal.index.creation.activator.SynonymSetIndexCreationBundleActivator.hasNoSynonymSetIndex(SynonymSetIndexCreationBundleActivator.java:67)
    [junit] 	at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:174)
    [junit] 	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
    [junit] 	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
    [junit] 	at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1374)
    [junit] 	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
    [junit] 	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
    [junit] 	at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)

Example test that is failing because of this:
https://testray.liferay.com/home/-/testray/case_results/936238152

Reproduced on:
Portal master git commit: c8a983065875bcad76254eb125cf75b902a6cde4