Interface to mark an authenticator as being stateless and able to emit a challenge exception when authentication fails.
An exception for stateless authenticators when credentials are wrong/missing.
Cookie Authenticator
Environment Authenticator
Form Authenticator
HttpBasic Authenticator
HttpDigest Authenticator
Session Authenticator with only ID
Authentication result object
Session Authenticator
Token Authenticator
An exception that signals that authentication was required but missing.