간단한 재고 시스템으로 알아보는 동시성 이슈 Stock @Entity public class Stock { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; private Long productId; private Long quantity; @Version private Long version; public Stock(){ } public Stock(Long productId, Long quantity) { this.productId = productId; this.quantity = quantity; } public Long getQuantity() { return quantity; } public void decrease..