@Override
    public OAuthService buildService(final WebContext context, final IndirectClient client) {
        init();

        val finalCallbackUrl = client.computeFinalCallbackUrl(context);

        return ((DefaultApi20) api).createService(this.key, this.secret, finalCallbackUrl, this.scope,
            this.responseType, null, null, this.httpClientConfig, null);
    }
{@inheritDoc}

Build an OAuth service from the web context.
pac4j-oauth/src/main/java/org/pac4j/oauth/config/OAuth20Configuration.java