import java.util.Optional; public class Main { static Optional<String> findCapital(String country) { if (country.equals("Norway")) { return Optional.of("Oslo"); } return Optional.empty(); } public static void main(String[] args) { Optional<String> country = Optional.of("Norway"); Optional<String> capital = country.flatMap(c -> findCapital(c)); System.out.println(capital.orElse("Not found")); } }