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  • EJB requires new

    Hi

    I have a problem with last project that integrates EJB, Spring and Hibernate.
    First, i would like to present architecture:

    WEB TIER -> EJBRemote ServiceA(BMT) -> Transaction Interceptor (Propagation Required, READ ONLY) -> POJO ServiceA (logic including some hibernate DAO)-> EJBLOCAL ServiceB(CMT) ->
    POJO ServiceB -> EJBLOCAL ServiceB(CMT) - REQUIRES NEW-> POJO ServiceB (login including some hibernate DAO).

    I realize that it looks quite weird - but it is all because of IBM folks who encourage to avoid transaction suspending in Websphere.

    Everything seems to work fine but the main problem is that SINGLE hibernate session is used by DAO executed in POJO ServiceA and POJO ServiceB.

    I see websphere trace files and all transactions are created as well.

    In logs i see:
    Code:
    javax.ejb.TransactionRolledbackLocalException:  ; nested exception is: org.springframework.dao.InvalidDataAccessApiUsageException: Write operations are not allowed in read-only mode (FlushMode.NEVER/MANUAL): Turn your Session into FlushMode.COMMIT/AUTO or remove 'readOnly' marker from transaction definition.
    Does anyone know how it is possible that sharing pre-bound hibernate session occurs between transactions ??

  • #2
    You don't say which version of Spring/WebSphere you are using.

    From Spring 2.1 there is support for a new WebSphereUOWTransactionManager that does allow suspend/resume semantics. This is available on WAS versions 6.0.2.19 or 6.1.0.9 or later:

    <bean id="transactionManager" class="org.springframework.transaction.jta.WebSphe reUowTransactionManager"/>

    Sara

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    • #3
      Hi
      Thanks for an answer.
      We are using Websphere bundled with RAD 7.0 so i do not exactly the version number, but as far as i know it is one of these that don't allow spring to suspend transactions smoothly .
      I also use Hibernate 3.2.2 and spring 2.0.2

      On production environment we will be using websphere 6.1 where spring transaction are fully supported but still i wanna to find a solution cause we are not sure if we won't try to port the application to websphere 6.0.

      Since my last post i have made more digging and noticed that after starting spring transaction, retrieving hibernate session (SessionUtils class) in DAOs returns the same Session object even if new container transactions are created.
      It all means that one session object is shared across JTA transactions.
      where the first transactions is created by spring and others by CMT.
      But the most important is that I must make more tests if the session object releases database connection properly, cause if not, it will be total mess.

      If anyone see any idea please share it

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