We have an issue with a byte array stored in a BINARY column.

We store a UUID in a BINARY(16) column. We convert the UUID to a byte[] before writing. We convert back from byte[] to UUID when reading.

We migrated from Spring-boot 2.6.8 to Spring-boot 2.7.1. The new 2.7.1 version comes with mariadb-java-connector:3.0.5 (with Spring-boot 2.6.X it was the 2.7.X versions).

With this new version, we have a NumberFormatException thrown when reading UUIDs from the DBs. The UUID is correctly stored as byte[], but read as String in the JDBC ResultSet.

How to reproduce

I created a repository to reproduce the issue. This repository contains a simple Entity, EntityWithUuid. There is a Spring Data JDBC repository, EntityWithUuidRepository and its related test, EntityWithUudRepositoryTest.

To reproduce the issue:

• Launch the Mariadb service with this command:
  docker-compose up -d
• Launch the test:
  ./gradlew test

Expected result: The test is successful.

Actual result: The test fails because of a ConversionFailedException