Message Driven Bean reading multiple times from a jms queue

Question

Hi,
I am facing a strange problem with my message driven bean. Its configured to read message from a jms queue. But sometimes it read the same message multiple times from the jms queue.
We are using weblogic server 8.1 sp5.
Please find below our descriptor files
ejb-jar.xml  
<ejb-jar>  
  <display-name>ClarifyCRM_Process_Manager_13.1</display-name>  
  <enterprise-beans>  
    <session>  
      <display-name>ProcessManager</display-name>  
      <ejb-name>ProcessManager</ejb-name>  
      <home>com.clarify.procmgr.ejb.ProcessManagerHome</home>  
      <remote>com.clarify.procmgr.ejb.ProcessManagerRemote</remote>  
      <ejb-class>com.clarify.procmgr.ejb.ProcessManagerEJB</ejb-class>  
      <session-type>Stateless</session-type>  
      <transaction-type>Container</transaction-type>  
    </session>  
    <message-driven>  
      <display-name>ProcessManagerListener</display-name>  
      <ejb-name>ProcessManagerListener</ejb-name>  
      <ejb-class>com.clarify.procmgr.ejb.ProcessManagerMDB</ejb-class>  
      <transaction-type>Bean</transaction-type>  
      <acknowledge-mode>Auto-acknowledge</acknowledge-mode>  
      <message-driven-destination>  
        <destination-type>javax.jms.Queue</destination-type>  
      </message-driven-destination>  
    </message-driven>  
  </enterprise-beans>  
  <assembly-descriptor>  
    <container-transaction>  
      <method>  
        <ejb-name>ProcessManager</ejb-name>  
        <method-name>*</method-name>  
      </method>  
      <trans-attribute>Required</trans-attribute>  
    </container-transaction>  
  </assembly-descriptor>  
</ejb-jar>  
weblogic-ejb-jar.xml  
<weblogic-ejb-jar>  
  <weblogic-enterprise-bean>  
    <ejb-name>ProcessManager</ejb-name>  
    <stateless-session-descriptor>  
      <pool>  
        <max-beans-in-free-pool>100</max-beans-in-free-pool>  
        <initial-beans-in-free-pool>10</initial-beans-in-free-pool>  
      </pool>  
    </stateless-session-descriptor>  
    <enable-call-by-reference>False</enable-call-by-reference>  
    <jndi-name>ProcessManagerHome</jndi-name>  
    <dispatch-policy>PMExecuteQueue</dispatch-policy>  
    <remote-client-timeout>0</remote-client-timeout>  
  </weblogic-enterprise-bean>  
  <weblogic-enterprise-bean>  
    <ejb-name>ProcessManagerListener</ejb-name>  
    <message-driven-descriptor>  
      <pool>  
        <max-beans-in-free-pool>100</max-beans-in-free-pool>  
        <initial-beans-in-free-pool>10</initial-beans-in-free-pool>  
      </pool>  
      <destination-jndi-name>clarify.procmgr.jms.queue.Execution</destination-jndi-name>  
      <connection-factory-jndi-name>clarify.procmgr.jms.factories.ExecConnection</connection-factory-jndi-name>  
    </message-driven-descriptor>  
    <enable-call-by-reference>True</enable-call-by-reference>  
    <dispatch-policy>PMListenerExecuteQueue</dispatch-policy>  
    <remote-client-timeout>0</remote-client-timeout>  
  </weblogic-enterprise-bean>  
</weblogic-ejb-jar>   The MDB is sometimes reading multiple times from clarify.procmgr.jms.queue.Execution
Also i would like to add here that the connection factory we are using clarify.procmgr.jms.factories.ExecConnection is having the following properties
ServerAffinity Enabled=true
XA connection factory enabled=false.
Please help me out here!!

Answer 1

Maybe, your MDB "sometimes" throws an Exception in onMessage.
Check if this happens when you set <max-beans-in-free-pool>1</max-beans-in-free-pool>.