It would be useful being able to see the diagram of a route defined in JavaDSL.

Despite being able to fully support a bi-directional linking between diagram and JavaDSL code is more complex to implement than XML based DSLs, the sub-problem of a mono-directional export from runtime to diagram should be easier to implement.

I'm suggesting this because I have found myself in the situation of needing the XML corresponding to the JavaDSL defined route, and I have written some code that was querying that data to a running instance.

A good use case for this functionality might be to create static diagrams from JavaDSL defined routes.

NOTE:
Discussing it with lheinema@redhat.com we agreed that it might be confusing for some user to see the functionality. The risk would be that they could think they can modify the diagram and have the corresponding JavaDSL modified (full bi-directional support).
To avoid this risk, in my opinion it should be enough to stress out that it's just an export operation; just like image editing programs work, allowing you to export your rich data format (like a psd) to a a flattened image (like jpg).