Role/Purpose of ContextLoaderListener in Spring?

Your understanding is correct. The ApplicationContext is where your Spring beans live. The purpose of the ContextLoaderListener is two-fold:

1. to tie the lifecycle of the ApplicationContext to the lifecycle of the ServletContext and

2. to automate the creation of the ApplicationContext, so you don’t have to write explicit code to do create it – it’s a convenience function.

Another convenient thing about the ContextLoaderListener is that it creates a WebApplicationContext and provides access to the ServletContext via ServletContextAware beans and the getServletContext method.