Transactional Patterns

Establish the boundary

• Inspect the project's Boot/Framework version, transaction manager, persistence technology, rollback configuration and caller before changing propagation.
• Place multi-step business transactions at the application/service boundary. Preserve Spring Data repository transactions; repository annotations are not inherently wrong.
• Default propagation is REQUIRED — joins existing transaction or creates one
• Use readOnly = true for appropriate read units of work. It is an optimization hint, not write prevention, authorization or automatic routing to a read replica.
• Keep existing architecture and transaction-manager choices. A local database transaction does not make writes to another database or an HTTP provider atomic.

The snippets below are illustrative; domain classes and imports come from the application. Adapt the service template and compare the good and bad examples when editing a service.