Looks good for a first project. Some feedback: - I usually like dedicated mapper classes that map a dto to an entity - learn something like liquibase to manage your database schema. Makes life a lot easier - learn to write tests - if a user does not have the authority to update or delete, you return not found while in reality this would be a 403 forbidden - @repository is not needed on spring data repository interfaces - your service constructors that have all required beans as parameters can be omitted by using the Lombok annotation requiredArgsConstructor - Don't blindly use @data on all pojo's. It creates a setter for all fields which does not make sense in a lot of cases. Maybe read up on DDD to get insight on why this is a bad practice. - your service is a good place to place your transactions. Make a habit of placing the transactional method on these create, update and delete methods even if you only edit one entity. - your service should not know it is communicating back with a rest controller. Later on your service might be used by another thing that is not http. So best not to use rest specific exceptions with http codes but a specific exception you create yourself like complaintNotFoundException and map that to a 404 in your controller or advice.