Java Optional: example with .ifPresentOrElse()

memberFinder.java

public void printMemberNameIfPresent(List<Member> members, int memberId) {
    members.stream()
        .filter(member -> member.getId() == memberId)
        .findFirst()
        .ifPresentOrElse(
            member -> printMemberFullName(member.getFullName()),    // if present, print successful message
            () -> printNoMemberMessage(memberId)                    // if absent, print unsuccessful message
        );
    }

    private static void printNoMemberMessage(int memberId) {
        System.out.println(String.format("Member with id %d is not a member", memberId));
    }

    private static void printMemberFullName(String memberFullName) {
        System.out.println(String.format("The member's full name is %s", memberFullName));
    }