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From Romain Manni-Bucau <>
Subject Re: Question on EJB and concurrency
Date Mon, 01 Sep 2014 09:41:41 GMT

1. true
2. @ConcurrencyManagement(BEAN -> lock free, @Lock(READ)
reentrantLock.readLock().lock/unlock is called (performance wise
difference is not that important in general)
3. it should. comparison is fair
4. @TransactionAttribute defines the transactional context you want,
required will create or inherit running tx, required_new will always
creates a new one. CDI beans are "support" (ie I don't care)

Romain Manni-Bucau
Twitter: @rmannibucau

2014-09-01 10:32 GMT+02:00 Lars-Fredrik Smedberg <>:
> Hi
> I have some questions on EJBs and concurrency, I hope someone can shed some
> light on the following questions:
> 1. I have understood that the annotations @ConcurrencyManagement and @Lock
> only are applicable to Singelton EJBs and that the default values are
> container managed concurrency and WRITE lock, correct?
> 2. What is the difference between annotating with
> @ConcurrencyManagement(BEAN) vs using container managed concurrency and
> annotating @Lock(READ) ? Is there better performance wise to use BEAN
> managed concurrency if thread safety is no issue?
> 3. Will an EJB annotate @ConcurrencyManagement(BEAN) simply ignore any
> @Lock annotations? Is this the EJB equivalent to an @ApplicationScoped CDI
> bean when it comes to concurrency?
> 4. Is this a totally separate function from using tx and annotation
> @TransactionAttribute ? I mean in the case of concurrent access to business
> method in a bean that e.g. has @TransactionAttribute(REQUIRED) I will start
> multiple transactions?
> Thanks
> Regards
> Lars-Fredrik
> --
> Med vänlig hälsning / Best regards
> Lars-Fredrik Smedberg
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