Is it necessary to create both application-context.xml and application-servlet.xml in a single application?

Question

• Why do we require a application-servlet.xml at all ?
• Why is application-context.xml alone insufficient?

Answer 1

It not necessary but recommended. Using separated configuration files you can isolate the web from the other world for security reasons(eg more secure). You can make a spring-boot program even without a single configuration file by annotations.

The application context is a bigger context, it means the beans defined in this context can be referred by servlet context but not vice versa.

Answer 2

Separation of concerns is just a best practice. No fire will suddenly appear if you ignore it, but you will have harder to maintain code. And if you carefully design your application with a web layer a service layer and a persistence layer, storing the beans in the proper application context will just make things simpler.