The normalized message router (NMR) is the part of the JBI environment that is responsible for mediating messages between JBI components; ServiceMix 4 has moved from JBI to OSGI. However, I read somewhere we still can use NMR without JBI based ServiceMix (JBI-free NMR). What does this mean? Any example that I can follow?
You can use ActiveMQ and JMS as the "JBI-free NMR". In fact it was ActiveMQ JMS queues that the JBI NMR uses under the covers.
In ServiceMix 4.x you can use Camel and JMS queues as your NMR if you want. And the messages do not need to be normalized anymore, eg they can be of any type, as opposed to JBI where the message must be XML.