Transaction synchronization in Spring Boot

Question

I have a small Spring Boot application with spring-boot-starter-web , spring-boot-starter-data-jpa , and postgresql as dependencies.

I'm able to use the @Transactional annotation and use JPA to fetch and save entities to the database. However, if I were to add afterCommit / afterCompletion hooks via registering a synchronization, it gives an IllegalStateException saying that Transaction synchronization is not active .

TransactionSynchronizationManager.registerSynchronization(
     new TransactionSynchronizationAdapter() {
        @Override
        public void afterCommit() {
            //this doesn't get called
            log.info("do something here");
        }
    });

Doing TransactionSynchronizationManager.initSynchronization(); gets rid of the error, but the hooks don't get called (eg: the afterCommit hook doesn't get called even though the transaction has committed.)

Any clues on how to debug this?

Answer 1

It turned out that I had forgotten to include the build plugin that is used to create the AoP-proxies for beans having @Transactional annotations.

In the absence of this plugin, no proxies would get generated, and the code would run non-transactionally; except for when it enters the JpaRepository methods where it would create a short-lived transaction for the duration of the call (such as save / findAll / delete ).

This is the plugin that I missed including in my pom.xml (this got generated in the pom output by the spring initializr ( https://start.spring.io/ ) but I didn't notice it at first and didn't copy it over into my pom)

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

Answer 2

I think you need @TransactionalEventListener annotation. It supports hooks BEFORE_COMMIT, AFTER_ROLLBACK, AFTER_COMPLETION, AFTER_COMMIT and AFTER_ROLLBACK.

More info in this post: Better application events in Spring Framework 4.2 .