Hi guys,

I am using Hibernate for my ORM needs with Tomcat as the application server. Since Tomcat doesnt have a default JTA offering, we are using JOTM to handle transactions.
But
- Commit and Rollback does not seem to happen with JOTM
- Is JOTM the best JTA implementation for Hibernate with Tomcat?
- What about BTM and Atomicos?
- Additionally I heard that JBOSS Transactions, which I opine would have been the perfect fit with Hibernate, does not work with Tomcat but only with JDBC. How far is this true?

Can any one suggest the best implementation for using JTA in Hibernate on Tomcat?

Thanks and Regards,
~Girish

This happens, when your DataSource is not JTA-aware.
(The DataSource XAResource has to be enlisted in the TransactionManager JOTM)



In following article you find examples for correctly using JTA with JOTM, BTM, Atomicos and JBossTM outside a EJB3Server.

http://community.jboss.org/wiki/ImplementingstandaloneJPAJTAHibernateapplicationoutsideJ2EEserverusingInfinispan2ndlevelcache

hope this helps

Thank you very much for your reply.
Just to clarify our scenario:
- We are not completely stand alone, we use Hibernate + JOTM on Tomcat 6.0.
- We have a transaction entry in our context.xml file

- We are also getting the hibernate session from JNDI on tomcat via a custom resource handler.
- Our hibernate cfg file looks like this


- Our persist logic looks like this


- But commit/rollback does not happen.

Can you pls advise us here.

Also I deploy my application as servlet on tomcat.
From this point of view this hiberante configuration is to consider standalone anyway
as it is not deployed in a managed ebj3 environment.



These properties above belong to a JDBC configuration (JDBCTransactionFactory) and have
no sense in a JTA environment (JTATransactionFactory).
You should remove this entries.
In a JTA environment YOU MUST REFER TO A DATASOURCE instead in your configuration.




If I remember right, hibernate tries to bind the sessionfactory to JDNI if you specify a session-factory name.
You don't need that, and moreover the binding can/will easily fail with certain JNDI-implementations.
Therefore: don't specify a name for the session factory





As I explained in the posting before, it is of fundamental importance to get the datasource jta-aware,
otherwise only DML-statements are propagated to the database but no commit/rollback.
Please take a deeper look a the examples in the linked article, especially the point where the datasource is defined.

All what's different in the examples in comparison to your environment,
is that they use JPA approach (= persistence.xml configuration file) whilst you use the classical hibernate configuration.
(just look for, how to refer a datasource in classical hibernate configuration)

thank you very much for your responses. Its adding a lot of value at some critical stages of ours.

- As per your suggestion, we changed the hibernate configuration to refer to a datasource



- In our context.xml we have this piece of code that tells hibernate to bind the session factory to JNDI



- Now Commit works, but Rollback fails. Any further insights on this?

How does the rollback fail. Is there an exception with stacktrace?

By the way: Why you intend to use JTA approach instead to use the default JDBC approach (JDBCTransactionFactory)?

There is no exception thrown. But it commits the data to the MySQL database.


We are using the JTA approach since we have 2 databases to work with. And this is our persistence code.

If I remember you can also activate some loggings on JOTM.
Check the logs and ensure that there it no any auto-commit happening.



The fact alone, that you have 2 databases to work with, does not mandatory require integration with JTA.
Only if you need also make both database participate to the same transaction, then you need JTA
(with fully XA-compliant jdbc-driver supporting the 2phase-commit).
Do you need both database participate to the same transaction ?

1. I will check the logs in JOTM; not sure how to do it but will find out.

2. Yes we have 2 databases participating in the same transaction

Ok.
One thing: Don't use XAPool as I used in my examples (wrapping non-xa-datasources as xa-datasource).

You probably have to use following as DataSource Classname if you use Mysql databases:
com.mysql.jdbc.jdbc2.optional.MysqlXADataSource

Please see also http://docs.sun.com/app/docs/doc/819-3658/gbsor?a=view
and http://dev.mysql.com/doc/refman/5.5/en/xa-restrictions.html

thanks for your reply. As per your advice I have changed the data source in Context.xml


I also changed web.xml to:


I have mysql-connector-java-5.0.8-bin.jar in my class path.

My hibernate.cfg.xml is:


I get a weird "Could not find datasource: java:/comp/env/jdbc/LocalYouDB". Any idea if I am making a mistake somewhere?

Seems that the step is missing which binds the datasource to JNDI.
(If you attach the complete stacktrace of the exception, then I could be more sure in the statement).
As I know tomcat offers a JNDI service, but it's some kind of read-only, so I'm not sure if it will work at all.
Anyway, If you don't are able to configure Tomcat in a way that it properly starts the datasource binding it to JNDI,
then as last resort you still can do start the datasource (and binds it to JNDI) manually in your hibernate-servlet similar as I did in the examples.

It could also happen that tomcat sucessfully binds the datasource (please check it in the tomcat logs),
but hibernate isn't able to resolve the datasource through jndi because using another jndi implementation.
In such case you must specify the proper jndi implementation in your hibernate configuration file:



(Unfortunately from Tomcat's documentation I was not able to find out ont the fly which implementation of jndi it is using per default.)

thanks so much for replying and helping out.

As per your advice, I changed the Datasource in JNDI to MySQLXADatasource.

Still the commit does not happen :( my tx.rollback() does not work. Not sure why.
This is taking away my sleep. See details below:

1. In context.xml


2. In Web.xml:


3. The hibernate.cfg.xml file is:


Is there anyway that I can send you the WAR / show you the code through a conf call?

I'm very busy now and whole next week I'm in vacation, sorry.
Try to startup the datasource manually in your servlet (as I do in the examples) , if tomcat is not able to do it for you.
The examples in my article are working, I tested them all and verified also that commit and rollback is working.