Problem For the Kakao Tech Campus final project, we built a student schedule management service. Manually entering timetables is tedious, so I wanted to implement automatic recognition when users ...
Problem During the Kakao Tech Campus final project, I implemented team chat functionality. Used WebSocket, worked fine locally. But after deploying to AWS ECS, problems arose. Instance A and B we...
Situation While implementing the Gift API at Kakao Tech Campus, I needed to integrate Kakao OAuth. I had to call Kakao’s API to get user info. The question was: use the traditional RestTemplate, ...
Situation While migrating the Gift API to JPA at Kakao Tech Campus, there was a requirement to delete options when a product is deleted. But the entity structure was unidirectional. @Entity publ...
Situation While implementing the Gift API at Kakao Tech Campus, a circular dependency occurred. MemberService → WishlistService → MemberService Spring threw BeanCurrentlyInCreationException. ...
Problem Discovery While implementing pagination for the Gift API at Kakao Tech Campus, a question came up: GET /api/wishlist?page=0&size=3&sort=product.name,desc What happens if a user ...
What I Didn’t Know While implementing pagination for the Gift API at Kakao Tech Campus, I used Spring Data JPA’s Page as the return type. Mentor told me something during code review: “Page int...
What Is the N+1 Problem? When fetching a parent entity and then accessing its child entities, instead of one query, N+1 queries are executed. List<Product> products = productRepository.find...
Question While implementing the Gift API at Kakao Tech Campus, I had to implement “delete wishlist item by product ID.” The question was: include productId in path or body? Option 1: DELETE /api/...
Situation While implementing the Gift API at Kakao Tech Campus, I had to validate whether a product exists when creating a wishlist item. Initially, I just tried to insert and caught DataIntegrity...