This is quite confusing. Did you resolved this issue ?
I am thinking maybe there is a import-package missing ?
Can you provide more information about it?
Such as which version of ServiceMix are you using?
com.sun.messaging.QueueConnectionFactory is implemented the javax.jms.ConnectionFactory, maybe something is wrong with the classloader?
Can you try to create the QueueConnectionFactory from the spring configure directly instead of looking up from the JNDI registry.