Spring Boot Interview Question - Transactional Trap

Transaction annotation trap in Spring Boot.

Scenario

Consider the following Spring service:

Assume:

• Spring’s default transaction configuration

• A relational database

• No custom rollback rules

Question

What happens when placeOrder() is invoked?

Options

A. The order is saved, the transaction commits, and notification fails
B. The order is NOT persisted because the transaction rolls back
C. No transaction is created at all
D. The application fails at startup

Correct Answer

B. The order is NOT persisted because the transaction rolls back

Explanation

• placeOrder() is annotated with @Transactional, so a single transaction is started when the method is entered.

• saveOrder() is called within the same class, so its own @Transactional annotation does not create a new transaction. when an @Transactional method, such as saveOrder(), is called from within the same object instance, its annotation is generally ignored because the transaction-intercepting proxy layer is bypassed.

• sendNotification() throws a RuntimeException.

• By default, Spring rolls back transactions on unchecked exceptions (RuntimeException, Error).

• Since everything runs inside the same transaction, the database changes made by saveOrder() are rolled back.

Result: No order is persisted.

Spring uses proxy-based AOP. Self-invocation bypasses the proxy, so the inner annotation is ignored.

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What if sendNotification() is moved to another Spring bean?

Yes, the transaction would still roll back — by default.