findProjectionsByUsername 생성오류

public interface MemberRepository extends JpaRepository<Member,Long>, MemberRepositoryCustom{


    @Query("select m from Member m where m.username=:name and m.age =:age")
    List<Member> findUser(@Param("name") String username, @Param("age") int age);

    @Query("select m.username from Member m")
    List<String> findUsernameList();

    @Query("select new study.datajpa.dto.MemberDto(m.id, m.username, t.name) from Member m join m.team t")
    List<MemberDto> findMemberDto();

    @Query("select m from Member m where m.username in :names")
    List<Member> findByNames(@Param("names") List<String> names);

//    @Query("select m from Member m",
//            countQuery = "select count(m.username) from Member m")
    Page<Member> findByAge(int age, Pageable pageable);

    @Modifying(clearAutomatically = true)
    @Query("update Member m set m.age=m.age+1 where m.age>=:age")
    int bulkAgePlus(@Param("age") int age);

    @Query("select m from Member m join fetch m.team")
    List<Member> findMemberFetchJoin();

    @EntityGraph(attributePaths = {"team"})
    List<Member> findByAge(@Param("age") int age);

    List<UsernameOnly> findProjectionsByUsername(String username);

}

public interface UsernameOnly {

    String getUsername();
}

혹시해서 이것도 올립니다

Member 클래스도 올려주실 수 있으세요?

@Entity
@Getter
@Setter
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@ToString(of = {"id","username","team"})
public class Member extends BaseEntity{

    @Id @GeneratedValue
    @Column(name = "member_id")
    private Long id;

    private String username;

    private int age;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "team_id")
    private Team team;

    public Member(String username) {
        this.username = username;
    }

    public Member(String username, int i, Team team) {
        this.username = username;
        this.age = i;
        if(team!=null){
            changeTeam(team);
        }
    }

    public Member(String username, int age) {
        this(username, age, null);
    }


    public void changeTeam(Team team){
        this.team = team;
        team.getMembers().add(this);
    }
}

혹시 Spring Data Jpa 버전이 최신버전이실까요?

만약 최신버전이시라면 아래 글 답변을 참고하셔서 Spring Boot 버전 또는 Spring Data Jpa 버전을 낮춰보시고 다시 시도해주시겠어요?

https://www.inflearn.com/questions/444705