How to call Rest webservice in Spring Security -

i have @restcontroller in web application, want make use of service in authentication provider security purpose .could please advise how achieve this? ( fyi : using spring boot)

for example rest service url : http://localhost:8080/authentication.json
login page url : http://localhost:8080/login

my question similar following question, difference is, rest service available in same application . hope rest template or httpurl connection not required ? please advise.
spring security login rest web service.

given below sample code snippet.

@restcontroller @requestmapping("authorize") public authorizecontroller{     @requestmapping(method = requestmethod.put, produces = "application/json")     public employee authorize(@requestparam string username) {          return employee;     } }  @configuration @enablewebmvcsecurity public class websecurityconfig extends websecurityconfigureradapter {     @autowired     customauthenticationprovider provider;      @override     protected void configure(httpsecurity http) throws exception {     }      @autowired     public void configureglobal(authenticationmanagerbuilder auth) throws exception {         auth.authenticationprovider(provider);                     } }  public class customauthenticationprovider implements authenticationprovider {     @override     public authentication authenticate(authentication authentication) throws authenticationexception {                   // here need call rest service . present in same application.     }      @override     public boolean supports(class<?> authentication) {         return authentication.equals(usernamepasswordauthenticationtoken.class);     } } 

thanks.