Java Optional: example with .isPresent() and .get()

memberFinder.java

public String memberNameById(List<Member> members, int memberId) {
    Optional<Member> maybeMember = members.stream()
        .filter(member -> member.getId() == memberId)
        .findFirst();               // returns an Optional
    
    if (maybeMember.isPresent()) {
        return maybeMember.get().getName();
    } else {
        return "UNKNOWN";
    }
}