I use a ServiceMix + Camel combo for integration purposes.
Two of my camel routes uses the NMR component to exchange messages. At startup I got the following exception if message were waiting to be processed:
ServiceMixException: Could not dispatch exchange. No matching endpoints.
I seems to be looking for a endpoint called xyz:enpoint_name
which is created a few seconds later
18:48:44,266 | INFO | xtenderThread-10 | ManagementEndpointRegistry | ement.ManagementEndpointRegistry 129 | 88 - org.apache.servicemix.nmr.management - 1.3.0.fuse-02-00 | Registering endpoint: org.apache.servicemix.nmr.core.InternalEndpointWrapper@e6810f84 with properties {CHANNEL_SYNC_DELIVERY=false, NAME=xyz:enpoint_name}
you can also use a route policy to control the startup/shutdown of routes, perhaps add a policy to check for the dependent route consumer prior to starting, etc...