How xx will be initialized from web.xml springs

How xx will be initialized from web.xml springs

Listener org.springframework.web.context.ContextLoaderListener calls
contextConfigLocation
through contextloader class as it extends it
{....
String configLocation =
servletContext.getInitParameter("contextConfigLocation");
...`enter code here`
}
enter code here
Listener org.springframework.web.util.Log4jConfigListener callsenter code
here log4jConfigLocation through some extended class { ... String location
= servletContext.getInitParameter("log4jConfigLocation"); .. }
Those are understandable as from servlet technology, context-params get
loaded whenever server starts up and we call it using
servletContext.getInitParameter() method.
Can somebody explain how Listeners will be initialized in Springs.