인프런 커뮤니티 질문&답변

안녕하세요 강의를 듣고 OrderServiceImpl클래스를 작성했는데 오류가 3가지 뜹니다

package hello.core.order;

import hello.core.discount.DiscountPolicy;
import hello.core.discount.FixDiscountPolicy;
import hello.core.member.Member;
import hello.core.member.MemberRepository;
import hello.core.member.MemoryMembereRepository;

public class OrderServiceImpl implements OrderService {

    private final MemberRepository memberRepository = new MemoryMembereRepository();
    private final DiscountPolicy discountPolicy = new FixDiscountPolicy();

    @Override
    public Order createOrder(Long memberId, String itemName, int itemPrice){
        Member member = memberRepository.findById(memberId);
        int discountPrice = discountPolicy.discount(member, itemPrice);

        return new Order(memberId, itemName, itemPrice, discountPrice);
    }
}

위 코드의 9번째 줄에서는 Class 'OrderServiceImpl' must either be declared abstract or implement abstract method 'creatOrder(Long, String, int)' in 'OrderService' 에러가

14번째 줄에서는 Method does not override method from its superclass,

16번째 줄에서는 Cannot resolve method 'findById' in 'MemberRepository'에러가 납니다 어떻게 고치면 해결될지 질문글 올립니다