Transaction Propagation in Spring, Spring Boot

What is Transaction Propagation ?

Propagation defines our business logic's boundary. Spring manages to start and pause a transaction based on our propagation setting.

In Spring Boot, we enable the transaction propagation using @Transactional annotation.

@Transactional : It Describes a transaction attribute on an individual method or on a class. 

We can set propagation, isolation, timeout, read-only and rollback conditions for our transaction using this annotation.

If annotation is applied at class level, then spring consider it for all the public methods, but if we applied at private or protected method then it ignores without an error.

Ex : 

  @Transactional(propagation = Propagation.REQUIRES_NEW)

  public void deleteExistingData() {

  }

Following are the settings for propagation

1.REQUIRED -  Default. Support a current transaction, create a new one if none exists.

2.SUPPORTS - Support a current transaction, execute non-transactionally if none exists.

3.MANDATORY - Support a current transaction, throw an exception if none exists. 

throw IllegalTransactionStateException

4.REQUIRES_NEW - Creates a new transaction, and suspend the current transaction if one exists.

5.NOT_SUPPORTED - Execute non transitionally, suspend the current transaction if one exists.

6.NEVER - Execute non-transitionally, throw an exception if a transaction exists.

7.NESTED - Execute within a nested transaction if a current transaction exists.