M03 Q14 What does transaction propagation mean?

Transaction propagation defines how existing transaction is re-used when calling @Transactional method with transaction already running.

Transaction propagation can be defined in @Transactional annotation in propagation field as one of following options:

• REQUIRED - support a current transaction, create a new one if none exists
• SUPPORTS - support a current transaction, execute non-transactionally if none exists
• MANDATORY - support a current transaction, throw an exception if none exists
• REQUIRES_NEW - create a new transaction, and suspend the current transaction if one exists
• NOT_SUPPORTED - execute non-transactionally, suspend the current transaction if one exists
• NEVER - execute non-transactionally, throw an exception if a transaction exists
• NESTED - execute within a nested transaction if a current transaction exists, behave like REQUIRED else