I have a DefaultMessageListenerContainer listening to a queue, and concurrentConsumers is set to 1. This works fine, but when I increase concurrentConsumers (e.g. to 3) the following exception appears repeatedly in the console:

Code:
14:31:38,165 ERROR org.springframework.jms.listener.DefaultMessageListenerContainer [listenerContainer-57]: Setup of JMS message listener invoker failed - trying to recover
javax.jms.JMSException: Connection[Oc4jJMS.Connection.PC96MYPC-T60.2fcf83d:116008c6ce2:-8000.119]: cannot create new session inside J2EE container when Session[Oc4jJMS.Session.PC96MYPC-T60.2fcf83d:116008c6ce2:-8000.120,false,AUTO_ACKNOWLEDGE] is currently active.
        at com.evermind.server.jms.JMSUtils.make(JMSUtils.java:1034)
        at com.evermind.server.jms.JMSUtils.toJMSException(JMSUtils.java:1114)
        at com.evermind.server.jms.JMSUtils.toJMSException(JMSUtils.java:1085)
        at com.evermind.server.jms.EvermindConnection.assertSession(EvermindConnection.java:493)
        at com.evermind.server.jms.EvermindConnection.createSession(EvermindConnection.java:204)
        at org.springframework.jms.listener.AbstractMessageListenerContainer.createSession(AbstractMessageListenerContainer.java:1002)
        at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.initResourcesIfNecessary(DefaultMessageListenerContainer.java:915)
        at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.invokeListener(DefaultMessageListenerContainer.java:903)
        at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.run(DefaultMessageListenerContainer.java:857)
        at org.springframework.core.task.SimpleAsyncTaskExecutor$ConcurrencyThrottlingRunnable.run(SimpleAsyncTaskExecutor.java:203)
        at java.lang.Thread.run(Thread.java:595)
Anyone who have seen this before? Have to mention that I'm quite new to JMS.. It seems like at least one consumer is instantiated, cause all the messages I send are consumed.

Btw, I'm using OC4J 10.1.3 and Spring 2.0.7, and my bean definition for the listenerContainer looks like this:
Code:
<bean id="listenerContainer"
      class="org.springframework.jms.listener.DefaultMessageListenerContainer">
   <property name="concurrentConsumers" value="3"/>
   <property name="connectionFactory" ref="jmsConnectionFactory" />
   <property name="destination" ref="myQueue" />
   <property name="messageListener" ref="myMessageListener" />
</bean>