Hi! If I use this property | @ActivationConfigProperty(propertyName="maxPoolSize", propertyValue="1") | I get this warning | 11:22:10,656 WARN [ServiceController] Problem starting service jboss.j2ee:ear=MessageServer.ear,jar=MessageServices.par,name=MessageListenerBean,service=EJB3 | org.jboss.deployment.DeploymentException: Error for ActivationSpec class com.sonicsw.sonicmq.j2ee.jmsra.impl.sonic.SonicActivationSpec as JavaBean; - nested throwable: (java.beans.IntrospectionException: No property found for: maxPoolSize on JavaBean: com.sonicsw.sonicmq.j2ee.jmsra.impl.sonic.SonicActivationSpec@34d234d2) | | Caused by: | java.beans.IntrospectionException: No property found for: maxPoolSize on JavaBean: com.sonicsw.sonicmq.j2ee.jmsra.impl.sonic.SonicActivationSpec@34d234d2 | If I use this property | @ActivationConfigProperty(propertyName = "maxSession", propertyValue = "1") | I get this warning | 11:34:46,828 WARN [ServiceController] Problem starting service jboss.j2ee:ear=MessageServer.ear,jar=MessageServices.par,name=MessageListenerBean,service=EJB3 | org.jboss.deployment.DeploymentException: Error for ActivationSpec class com.sonicsw.sonicmq.j2ee.jmsra.impl.sonic.SonicActivationSpec as JavaBean; - nested throwable: (java.beans.IntrospectionException: No property found for: maxSession on JavaBean: com.sonicsw.sonicmq.j2ee.jmsra.impl.sonic.SonicActivationSpec@4e744e74) | | Caused by: | java.beans.IntrospectionException: No property found for: maxSession on JavaBean: com.sonicsw.sonicmq.j2ee.jmsra.impl.sonic.SonicActivationSpec@4e744e74 | Does anyone know another way to implement singleton MDB? Br, Sami View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4006743#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...