@ApplicationScoped
public class DynamicConfigUsageSample {

    private @Inject Config config;

    private ConfigValue<String>  serverUrlCfg;
    private ConfigValue<Integer> serverPortCfg

    @PostConstruct
    private void init() {
        serverUrlCfg= config.access("com.acme.myproject.someserver.url")
                .cacheFor(5, TimeUnit.MINUTES)
                .logChanges(true)
                .evaluateVariables(true);

        serverPortCfg = config.access("com.acme.myproject.someserver.port")
                .as(Integer.class)
                .cacheFor(5, TimeUnit.MINUTES)
                .logChanges(true)
                .evaluateVariables(true)
                .withDefault(8080);
    }

    public void useTheConfig() {
        callToServer(serverUrlCfg.getValue(), serverPortCfg.getValue());
    }
}