title: GWT Deferred binding failed for custom class: No class matching "..." in urn:import:
body: <p>I am developing a couple of custom widgets that I would like to be able to use with UiBinder. Unfortunately I keep wasting my life away with chasing down the following error:</p>
  
  <p>No class matching "..." in urn:import:...</p>
  
  <p>This seems to be the catch-all exception that is thrown any time there is <strong>any</strong> error in the class that prevents the GWT compiler from processing it. This includes anything in the class's entire dependency tree.</p>
  
  <p>To save myself and anyone of you who is running into the same issue some time and pain, let's compile a list here of the most unexpected and hard to find causes for this. I'll start with my latest one, which has made me decide to post this here.</p>