JSON response for invalid authorization differs from other error types and is not documented

[zyga]

I was working with the management API and I used incorrect authorization credentials. To my surprise the 401 error was combined with a different error serialization response:

{
  "timestamp": "...",
  "status": 401,
  "error": "Unauthorized",
  "message": ""
}

I suspect this is coming from another layer, perhaps from Spring? I think this response should be documented somewhere.