Spring MVC applications often require additional configuration files, depending on the specific needs of the application. These files typically contain information necessary to establish and configure most of the components in the application. A common example is a Servlet configuration file, which describes how to map different URL paths to servlets, filters and other components. Further, the application may need Java-based configuration for bean mappings or security constraints. The application can also specify property files for defining values needed by various services during runtime. Finally, deployment descriptor XML files are necessary for declaring Struts action classes and other related information about the deployed environment. Although all of these configurations may seem complex at first glance, they are all needed in order to define correctly each part of the Spring MVC application. However, once configured correctly an Spring MVC application behaves reliably in any environment without any manual changes or prompts from users. Thus, when answering a Spring MVC interview question about what additional configurations an application needs it is important to consider all those mentioned above along with any other requirements specified by your project team's guidelines.