You are using NonManagedConnectionFactory, which is does not pool the connection. The stack trace shows that the driver tries to create a new physical connection to the database(no driver pooling) , so it might be a problem with driver not being able to cope with such a high frequency of connections being released/acquired. Can you please try it again, this time with a C3p0ConnectionFactory? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4101730#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...