播放 2.5 - @Transactional readOnly 被忽略了？

Question

I have a Java Play 2.5 application, and I have a transaction marked as readonly (at the Controller level):

    @Transactional(readOnly = true)
    public Result list() { ...

(this is the play.db.jpa.Transactional annotation).

So, if I turn on logging for hibernate transaction:

 <logger name="org.hibernate.engine.transaction" level="TRACE"/>

Then I see the transaction being made and being committed.

019-12-03 23:42:23,754 [debug] from org.hibernate.engine.transaction.jta.platform.internal.JtaPlatformInitiator in main - No JtaPlatform was specified, checking resolver
2019-12-03 23:42:23,755 [debug] from org.hibernate.engine.transaction.jta.platform.internal.JtaPlatformResolverInitiator in main - No JtaPlatformResolver was specified, using default [org.hibernate.engine.transaction.jta.platform.internal.StandardJtaPlatformResolver]
2019-12-03 23:42:23,766 [debug] from org.hibernate.engine.transaction.jta.platform.internal.StandardJtaPlatformResolver in main - Could not resolve JtaPlatform, using default [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2019-12-03 23:58:46,769 [debug] from org.hibernate.engine.transaction.internal.TransactionImpl in application-akka.actor.default-dispatcher-5 - begin
2019-12-03 23:58:46,878 [error] from application in application-akka.actor.default-dispatcher-5 - Transaction: org.hibernate.engine.transaction.internal.TransactionImpl@3d505ddd[transactionCoordinator=org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl@89a1241,exceptionConverter=org.hibernate.internal.ExceptionConverterImpl@76f0443c,transactionDriverControl=org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl@49f1518a]
2019-12-03 23:59:27,638 [debug] from org.hibernate.engine.transaction.internal.TransactionImpl in application-akka.actor.default-dispatcher-5 - committing

However, I have one problem - it's not read-only! I've added some code that modifies an object (obj.setField("changed value")), and it's saved into the database at the end of the transaction!

I was expecting an exception telling me that the transaction is read-only and that it cannot be committed!

1. Why it the transaction not read-only?
2. Can I somehow see in logs if Hibernate creates the transaction readonly or not?

Other info: Java Play 2.5.10, Hibernate 5 (5.2.6), and PostgreSQL as the DB.

Answer 1

So, it seems that it was because the controller class itself was annotated with @Transactional, and the method with @Transactional(readOnly=true).

Somehow, the class annotation overrides the method annotation. This doesn't seem logical to me, but in practice, that seems to be the case: as soon as I've removed the @Transactional from the class level, it worked just fine.