service_discovery.java

    private void startServiceConfig() {
        Log.i(TAG, "Starting service config");

        String discoveryEndpoint = app.getString(R.string.discovery_endpoint);
        if (discoveryEndpoint.trim().length() == 0 || !URLUtil.isValidUrl(discoveryEndpoint)) {
            Log.i(TAG, "Using static service config");
            AuthorizationServiceConfiguration serviceConfig =
                    new AuthorizationServiceConfiguration(
                            Uri.parse(app.getString(R.string.authorization_endpoint)),
                            Uri.parse(app.getString(R.string.token_endpoint)));
            authState = new AuthState(serviceConfig);
            userInfoUrl = app.getString(R.string.user_info_endpoint);

            finishServiceConfig();
        } else {
            Log.i(TAG, "Using discovery service config");
            Uri discoveryUri = Uri.parse(discoveryEndpoint);
            loginListener.onEvent(AuthRepo.this, AUTH_SERVICE_DISCOVERY_START);

            AuthorizationServiceConfiguration.fetchFromUrl(discoveryUri, this::finishServiceDiscovery);
        }
    }

    private void finishServiceDiscovery(AuthorizationServiceConfiguration config,
            AuthorizationException ex) {
        if (config == null) {
            failLogin(new AuthException("Failed to retrieve authorization service discovery document"));
            return;
        }

        authState = new AuthState(config);
        AuthorizationServiceDiscovery discovery = config.discoveryDoc;
        userInfoUrl = discovery.getUserinfoEndpoint().toString();

        loginListener.onEvent(AuthRepo.this, AUTH_SERVICE_DISCOVERY_FINISH);

        finishServiceConfig();
    }