Simple OAuth2 Resource Owner Password Credentials.
#GetAccessToken
This will add the necessary oAuth headers to each request.
  public interface IOauthService {
    @POST("/oauth/token")
    void getAccessToken(@Body AccessTokenRequest accessTokenRequest,
                        Callback<AccessTokenResponse> responseCallback);
}#Send Token Every Request
   RequestInterceptor requestInterceptor = new RequestInterceptor() {
        @Override
        public void intercept(RequestFacade request) {
            request.addHeader("Authorization", "Bearer" + token);
            request.addHeader("User-Agent", "Android");
        }
    };