How would you design an audit logging system for every database change?

For simple field-level tracking, Spring Data's @CreatedDate/@LastModifiedDate/@CreatedBy/@LastModifiedBy with @EnableJpaAuditing cover who/when. For a full change history, use Hibernate Envers (automatic revision tables) or write changes to a separate audit_log table inside the same transaction as the business write, capturing old/new values and the acting user.