Squashed commit of the following:

commit d14a8a37daa4eff712f77c22acc7906de09eac47
Author: Kam Kasravi <kamkasravi@yahoo.com>
Date:   Tue Aug 19 18:15:16 2014 -0700

    Define all GET noArgs to return BAD_REQUEST when a path component is missing
Yes ErrorResponse holds some helpful text and the error code (http status code). Current behavior is that the client will get an HTTP status code (eg 400) and a small JSON body that holds this information. 

You're also correct that the exception mapper handles uncaught exceptions. I think Suneel's suggested change is we throw an exception from each Response.getNoArgs() method which is then caught by the @Provider exceptionmapper which then writes basically what we're doing now in these getNoArgs() methods. Yes I agree it seems to be a bit oblique. This doesn't mean we shouldn't define an exceptionmapper to catch unhandled exceptions where we could possibly differentiate where the exception occurred and embed the stack trace back to the client. I think this could be useful vs the flat 500 response.