Misleading Responses on OAuth Request, 401 Invalid Signature

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Using sample OAuth code, call:
requestToken = oauthService.getOAuthRequestToken(callbackUrl);
without or with null callbackUrl.
2. System attempts to make authorisation.
3. LinkedIn responds with 401: Invalid Signature 

What is the expected output? What do you see instead?
It may be better to throw an exception before sending off to LinkedIn 
indicating no callbackUrl provided. This was causing us hell trying to work out 
where it went wrong, simply because LinkedIn's response was so convincing! The 
actual error was in our code miles away to do with config... 

What version of the product are you using? On what operating system?
Latest (6 Sept 2010), Mac OS X Snow Leopard 10.6.6

NB: This maybe better in the 'gotchas' pile

Original issue reported on code.google.com by mich...@wawra.co.uk on 25 Jan 2011 at 7:49