Java Optional: method that might throw a NullPointerException

memberFinder.java

public Member memberById(List<Member> members, int memberId) {
    List<Member> maybeMembers = members.stream()
        .filter(member -> member.getId() == memberId)
        .collect(Collectors.toList());
    
    if (maybeMembers.size() > 0) {
        return maybeMembers.get(0);
    } else {
        return null;
    }
}