HTTP Docs: HTTP Basic Authentication Made Easy
BasicAuthenticationFilter
The BasicAuthenticationFilter is an implementation of the AuthenticationFilter interface. It returns a structure which will contain both a username and password key with respective values if and only if the page context request under which the method was invoked contained a properly formatted "authorization" header containing base64 encoded http basic authentication credentails. If the header exists, then the structure will be populated correctly. If no such header exists, then an empty structure will be returned;