I upgraded Spring Boot to 1.4.2 and Hibernate to 5.0.11.Final and started seeing this error. Not sure why HibernateJpaAutoConfiguration is registering the custo
Somehow the @EnableAutoconfiguration of JPA were passing two paths to get scanned, because the database configuration was in sub folder which makes sense.
com.testOrg
com.testOrg.configuration
org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager on line 520 is adding converters multiple times based on the number of scanned configuration paths found,
I think for other classes we do not have check for duplicacy but for Converters we do have check if it gets registered multiple times than throw Exception see. com.testOrg.configuration.MetadataBuilderImpl.java line 907
To solve this, I moved my DatabaseConfiguration class out of "com.testOrg.configuration" folder to main and hence only one class to register.
I hope this might be helpful for someone.