Hibernate,Kotlin没有可空ID属性 Hibernate实体ID ID Kotlin Nullable타입을지정해줘야다。 @Table(name = " GRP_GROUP " ) @Entity(name = " Group " ) class Group ( @Id @GeneratedValue(strategy = GenerationType . SEQUENCE , generator = " SEQ_GROUP " ) @SequenceGenerator(name = " SEQ_GROUP " , sequenceName = " SEQ_GROUP " , allocationSize = 1 ) @Column(name = " GROUP_KEY " , unique = true , nullable = false