Issue Summary

This is reproducible on Data Center: yes (Single Node Data Center with bundled search server)

Steps to Reproduce

1. Start Bitbucket 7.21.0 or higher with the bundled search server using Java 11
2. Complete the setup process (if it is not yet completed)

Expected Results

There are no warnings logged by the bundled search server.

Actual Results

After Bitbucket setup is completed (or after Bitbucket startup if the setup was already completed on a previous start), the following is logged to the console that started Bitbucket:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.opensearch.security.support.Base64Helper$DescriptorNameSetter (file:/opt/atlassian/bitbucket/atlassian-bitbucket-7.21.1/opensearch/plugins/opensearch-security/opensearch-security-1.2.4.0.jar) to field java.io.ObjectStreamClass.name
WARNING: Please consider reporting this to the maintainers of org.opensearch.security.support.Base64Helper$DescriptorNameSetter
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

This will only be logged once per (re)start of Bitbucket and the bundled search server. Note that search functionality is not impacted.

Workaround

This is a known bug in OpenSearch, and does not have any impact on the search server. It is effectively a deprecation warning for Java functionality that won't be available in later Java versions, and can safely be ignored. Bitbucket will always bundle an appropriate JVM that can be used by both Bitbucket and the bundled search server.

The warnings will not be logged when running the bundled search server with Java 8.