In the Web MVC framework, each DispatcherServlet has its own WebApplicationContext, which inherits all the beans already defined in the rootWebApplicationContext. These inherited beans can be overridden in the servlet-specific scope, and you can define new scope-specific beans local to a given Servlet instance.

  https://docs.spring.io/spring-framework/docs/3.2.x/spring-framework-reference/html/mvc.html