Race Condition in JPA

References

• https://stackoverflow.com/questions/29574630/how-to-avoid-race-conditions-on-product-sales-with-jpa-and-hibernate
• https://softwareengineering.stackexchange.com/questions/133925/best-practice-to-manage-concurrency-into-a-basket-in-a-e-commerce-website
• https://stackoverflow.com/questions/35465008/managing-the-product-count-in-the-database