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POCannot create and close multiple EntityManagers in a SessionBean method
 

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  1. POCannot create and close multiple EntityManagers in a SessionBean method
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    <p>I'm trying to use OpenJPA Slice as a persistence mechanism for one of my classes inside a JBoss 4.0.5 (EJB 2.1) application server and I'm experiencing some problems.</p> <p>In a J2SE setting the following code (create an EntityManager, use it, close it, create a new one, use it close it) works fine.</p> <pre><code>EntityManagerFactory factory = Persistence.createEntityManagerFactory("my_persistence_unit"); EntityManager em = factory.createEntityManager(); Query q = em.createQuery("select m from mytable m"); List result = q.getResultList(); // ... do something with result em.close(); em = factory.createEntityManager(); q = em.createQuery("select m from myothertable m"); result = q.getResultList(); // ... do something with result em.close(); </code></pre> <p>But if I try to do the same thing in a StatelessSessionBean (again: EJB 2.1)</p> <pre><code>// the entity manager FACTORY is a static variable defined elsewhere EntityManager em = FACTORY.createEntityManager(); Query q = em.createQuery("select m from mytable m"); List result = q.getResultList(); // ... do something with result em.close(); em = FACTORY.createEntityManager(); q = em.createQuery("select m from myothertable m"); result = q.getResultList(); // ... do something with result em.close(); </code></pre> <p>... I get an exception on the second query execution:</p> <pre><code>&lt;openjpa-1.0.1-r420667:592145 fatal user error&gt; org.apache.openjpa.persistence.InvalidStateException: The context has been closed. </code></pre> <p>The same thing happens if I have only one query in my SessionBean method and I remote call it twice. The first call works just fine but the second call would throw the same exception.</p> <p>It seems like all queries in the SessionBean are executed against the context of the first EntityManager ever created in the session bean. If I don't call close() on the first EntityManager, everything works fine.</p> <p>I'm puzzled why there's any interference between SessionBeans and JPA EntityManagers at all since JBoss 4 is so old that it shouldn't know anything about JPA.</p> <p>This is the persistence.xml for the J2SE setup: com.mycompany.MyEntity</p> <pre><code> &lt;properties&gt; &lt;property name="openjpa.BrokerFactory" value="slice"/&gt; &lt;property name="openjpa.slice.Names" value="One,Two"/&gt; &lt;property name="openjpa.slice.Master" value="One"/&gt; &lt;property name="openjpa.slice.Lenient" value="true"/&gt; &lt;property name="openjpa.slice.One.ConnectionURL" value="jdbc:mysql://localhost/jpa_test_1"/&gt; &lt;property name="openjpa.slice.Two.ConnectionURL" value="jdbc:mysql://localhost/jpa_test_2"/&gt; &lt;property name="openjpa.slice.DistributionPolicy" value="com.mycompany.RandomDistributionPolicy"/&gt; &lt;property name="openjpa.ConnectionDriverName" value="com.mysql.jdbc.Driver"/&gt; &lt;property name="openjpa.ConnectionUserName" value="user"/&gt; &lt;property name="openjpa.ConnectionPassword" value="password"/&gt; &lt;property name="openjpa.jdbc.SynchronizeMappings" value="buildSchema"/&gt; &lt;!-- --&gt; &lt;/properties&gt; &lt;/persistence-unit&gt; </code></pre> <p>This is the persistence.xml for the JBoss setup:</p> <pre><code>&lt;persistence-unit name="my_persistence_unit" transaction-type="RESOURCE_LOCAL"&gt; &lt;class&gt;com.mycompany.MyEntity&lt;/class&gt; &lt;properties&gt; &lt;property name="openjpa.BrokerFactory" value="slice"/&gt; &lt;property name="openjpa.slice.Names" value="One"/&gt; &lt;property name="openjpa.slice.Master" value="One"/&gt; &lt;property name="openjpa.slice.Lenient" value="true"/&gt; &lt;property name="openjpa.ConnectionUserName" value="user"/&gt; &lt;property name="openjpa.ConnectionPassword" value="password"/&gt; &lt;property name="openjpa.slice.One.ConnectionURL" value="jdbc:mysql://localhost/jpa_test_1"/&gt; &lt;property name="openjpa.slice.One.ConnectionDriverName" value="com.mysql.jdbc.Driver"/&gt; &lt;property name="openjpa.slice.Two.ConnectionURL" value="jdbc:mysql://localhost/jpa_test_2"/&gt; &lt;property name="openjpa.slice.Two.ConnectionDriverName" value="com.mysql.jdbc.Driver"/&gt; &lt;property name="openjpa.slice.ThreadingPolicy" value="cached"/&gt; &lt;property name="openjpa.slice.DistributionPolicy" value="com.mycompany.RandomDistributionPolicy"/&gt; &lt;property name="openjpa.jdbc.DBDictionary" value="mysql"/&gt; &lt;property name="openjpa.jdbc.SynchronizeMappings" value="buildSchema"/&gt; &lt;property name="openjpa.Log" value="DefaultLevel=INFO, Runtime=TRACE, Tool=INFO, SQL=TRACE"/&gt; &lt;property name="openjpa.jdbc.QuerySQLCache" value="false"/&gt; &lt;/properties&gt; &lt;/persistence-unit&gt; </code></pre>
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    1. This table or related slice is empty.
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    1. PTQuestion
    1. USsme
    1. USsme
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    1. This table or related slice is empty.
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    1. This table or related slice is empty.
    1. VO
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      1. POCannot create and close multiple EntityManagers in a SessionBean method
      1. This table or related slice is empty.
      1. VTUpMod
    1. COJBoss 4 might not be aware of JPA, but JPA is probably aware of the container around it (and its sessionContext and the associated transaction). Try to split your SSB into two ones: Each one gets only one *PersistenceContext* *injected* (not *PersistenceUnit*). Then call these two from another SSB. All should use CMT. BTW show the persistence.xml of both persistence units. You possibly have to change these to using a JTA data source.
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      1. POCannot create and close multiple EntityManagers in a SessionBean method
      1. USBeryllium
    2. CO@Beryllium unfortunately there's no injection going on here. JBoss 4 doesn't do it for me. So I have to programmatically create an EntityManager.
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      1. POCannot create and close multiple EntityManagers in a SessionBean method
      1. USsme
    3. COOops, yes, no injection. Another idea is to use BMT with `TransactionAttributeType.NOT_SUPPORTED`, just to make sure that there is not TX provided by the container (so that JPA does not use that one).
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      1. POCannot create and close multiple EntityManagers in a SessionBean method
      1. USBeryllium
 

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