Spring Boot Transaction Management Concepts Questions and Answers

Question 1

An `OrderService` method, annotated with `@Transactional`, calls a public method in an `InventoryService` bean which is annotated with `@Transactional(propagation = Propagation.REQUIRES_NEW)`.
If the `InventoryService` method completes successfully, but an unhandled exception is thrown later within the `OrderService` method, what will be the final state of the database changes?

Accepted Answer

Changes made by `InventoryService` will be committed, while changes made by `OrderService` will be rolled back.

Answer

All changes from both services will be rolled back.

Answer

All changes from both services will be committed because the exception was unhandled.

Answer

The outcome is non-deterministic and depends on the database isolation level.

Question 2

What is the primary benefit of marking a transactional method with `@Transactional(readOnly = true)` in a Spring Boot application using JPA and Hibernate?

Accepted Answer

It signals to the underlying persistence provider to apply performance optimizations, such as disabling dirty checking.

Answer

It prevents the method from performing any write operations by throwing an exception if one is attempted.

Answer

It automatically sets the transaction isolation level to `READ_UNCOMMITTED` for better performance.

Answer

It ensures that the method will not participate in any existing transaction and will always run non-transactionally.

Question 3

In a Spring Boot application, if a public method in a `@Service` bean is annotated with just `@Transactional` and throws a `RuntimeException` during its execution, what is the expected default transactional behavior?

Accepted Answer

The transaction will be rolled back.

Answer

The transaction will be committed because only checked exceptions trigger a rollback by default.

Answer

The transaction will be committed because no propagation level was specified.

Answer

The behavior is undefined and requires explicit configuration of `rollbackFor`.

Question 4

A financial reporting service needs to run a long-running transaction that reads multiple rows, performs complex calculations, and then reads the same rows again to verify data consistency. It is critical that the data from the initial read does not change during the transaction. Which transaction isolation level should be used to prevent this "non-repeatable read" phenomenon?

Accepted Answer

REPEATABLE_READ

Answer

READ_COMMITTED

Answer

READ_UNCOMMITTED

Answer

SERIALIZABLE

Question 5

A developer has a Spring `@Service` bean with two public methods. The first method, `processData()`, is not transactional. It calls the second method within the same class, `saveData()`, which is annotated with `@Transactional`. When an external bean calls `processData()`, what happens to the transaction for the `saveData()` call?

Accepted Answer

The call to `saveData()` is executed, but no transaction is created.

Answer

A new transaction is started correctly for the `saveData()` method.

Answer

An `IllegalStateException` is thrown because a non-transactional method is calling a transactional one.

Answer

The entire `processData()` method becomes transactional automatically.

Question 6

Which of the following scenarios is the most compelling reason to use programmatic transaction management with `TransactionTemplate` instead of the declarative `@Transactional` annotation?

Accepted Answer

When you need to implement transaction logic with finer-grained control, such as starting and committing multiple distinct transactions within a single business method.

Answer

When a method needs to operate on multiple data sources.

Answer

When managing transactions on private methods within a bean.

Answer

When developing applications that must be portable across different transaction managers.