How to use @Transactional annotation in Spring boot

Question

I am working on a spring-boot project.

Before using @Transactional annotation in my project I have two questions

1. Best practice to use @Transactional annotation in spring-boot, service layer or DAO layer?

2. If the service layer then where do I use the @Transactional annotation on a class or on a method in that class?

Answer 1

1. in the service layer: you want your whole business method to be ACID
2. on the class if you want all bean methods to be transactional, on the method if you want that specific method to be transational, or to have different transactional attributes