인프런 커뮤니티 질문&답변

import jakarta.persistence.EntityManager;
import jakarta.persistence.EntityManagerFactory;
import jakarta.persistence.EntityTransaction;
import jakarta.persistence.Persistence;

public class Test {
    public static void main(String[] args) {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("hello");
        EntityManager em = emf.createEntityManager();
        EntityTransaction tx = em.getTransaction();
        tx.begin();
        try {
            Team team = new Team();
            team.setName("team1");
            em.persist(team);

            Member member = new Member();
            member.setName("hi");
            member.setTeam(team);
            em.persist(member);

            em.flush();
            em.clear();

            Member findMember = em.find(Member.class, member.getId());
            System.out.println(findMember.getTeam().getClass());
            System.out.println(findMember.getTeam().getName());
            System.out.println("=========");

            Team team2 = new Team();
            team2.setName("team2");
            em.persist(team2);
            findMember.setTeam(team2);

            em.flush();
            em.clear();

            Member findMember2 = em.find(Member.class, member.getId());

            System.out.println(findMember2.getTeam().getClass());
            System.out.println(findMember2.getTeam().getName());

            tx.commit();
        } catch (Exception e) {
            tx.rollback();
            e.printStackTrace();
        } finally {
            em.close();
        }

        emf.close();
    }
}

실행결과

Hibernate: 
    /* insert for
        jpa_basic.ex1_hello_jpa.entity.Team */insert 
    into
        Team (name, TEAM_ID) 
    values
        (?, default)
Hibernate: 
    /* insert for
        jpa_basic.ex1_hello_jpa.entity.Member */insert 
    into
        Member (city, name, number, roleType, street, TEAM_ID, zipcode, MEMBER_ID) 
    values
        (?, ?, ?, ?, ?, ?, ?, default)
Hibernate: 
    select
        m1_0.MEMBER_ID,
        m1_0.city,
        m1_0.name,
        m1_0.number,
        m1_0.roleType,
        m1_0.street,
        m1_0.TEAM_ID,
        m1_0.zipcode 
    from
        Member m1_0 
    where
        m1_0.MEMBER_ID=?
class jpa_basic.ex1_hello_jpa.entity.Team$HibernateProxy$q7Fz4jvQ
Hibernate: 
    select
        t1_0.TEAM_ID,
        t1_0.name 
    from
        Team t1_0 
    where
        t1_0.TEAM_ID=?
team1
=========
Hibernate: 
    /* insert for
        jpa_basic.ex1_hello_jpa.entity.Team */insert 
    into
        Team (name, TEAM_ID) 
    values
        (?, default)
Hibernate: 
    /* update
        for jpa_basic.ex1_hello_jpa.entity.Member */update Member 
    set
        city=?,
        name=?,
        number=?,
        roleType=?,
        street=?,
        TEAM_ID=?,
        zipcode=? 
    where
        MEMBER_ID=?
Hibernate: 
    select
        m1_0.MEMBER_ID,
        m1_0.city,
        m1_0.name,
        m1_0.number,
        m1_0.roleType,
        m1_0.street,
        m1_0.TEAM_ID,
        m1_0.zipcode 
    from
        Member m1_0 
    where
        m1_0.MEMBER_ID=?
class jpa_basic.ex1_hello_jpa.entity.Team$HibernateProxy$q7Fz4jvQ
Hibernate: 
    select
        t1_0.TEAM_ID,
        t1_0.name 
    from
        Team t1_0 
    where
        t1_0.TEAM_ID=?
team2

안녕하세요 위 코드에 대해 질문 있습니다.

findMember.getTeam().getClass() 출력결과가
class jpa_basic.ex1_hello_jpa.entity.Team$HibernateProxy$q7Fz4jvQ 와 같습니다.

그리고 findMember2.getTeam().getClass(); 출력결과가 class jpa_basic.ex1_hello_jpa.entity.Team$HibernateProxy$q7Fz4jvQ 와 같습니다.

중간에 clear()를 하여 영속성 컨텍스트를 비웠는데 왜 프록시 객체를 조회하면 똑같은 프록시 객체가 나오는지 궁금합니다.