Question

I know that the default rollback policy within the Transaction Manager is automatic rolling back when RuntimeExceptions occur. Though, what happens if I have a checked exception that is allowed to propagate?

Answer 1

However, please note that the Spring Framework’s transaction
infrastructure code will, by default, only mark a transaction for
rollback in the case of runtime, unchecked exceptions; that is, when
the thrown exception is an instance or subclass of RuntimeException.
(Errors will also – by default – result in a rollback.) Checked
exceptions that are thrown from a transactional method will not result
in the transaction being rolled back.

Source

Even if checked exception is thrown, Spring will commit the transaction as if everything is fine.
If required you can configure a rollback on a checked exceptions.
Like

<tx:advice id="txAdvice" transaction-manager="txManager">
  <tx:attributes>
     <tx:method name="get*" read-only="false" rollback-for="AnyCheckedException"/>
     <tx:method name="*"/>
  </tx:attributes>
</tx:advice>

Will perform a rollback when AnyCheckedException is thrown.

This might help : Spring transaction management with checked and unchecked exception