Explain how you can handle static resources in Spring MVC.

Question

Accepted Answer

Static resource handling in Spring MVC is the mechanism that lets the framework serve non-dynamic files — CSS, JavaScript, images, fonts — directly from a configured location without routing them through a controller.

Key Points:
• WebMvcConfigurer's addResourceHandlers method maps a URL pattern to one or more physical or classpath locations.
• Common locations include classpath:/static/, classpath:/public/, or /resources/ under the webapp root.
• Resource handlers can enable HTTP caching headers so browsers cache static assets and avoid re-fetching them on every request.
• In plain Spring MVC (non-Boot), @EnableWebMvc is needed to activate the MVC configuration that resource handling relies on.
• Spring Boot auto-configures sensible static resource handling out of the box, so manual setup is only needed to customize it.

Example:
Requesting /css/site.css in the browser gets matched against a registered pattern like "/css/**" and served from classpath:/static/css/site.css, without ever invoking a controller method.

Code Example:
```
@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/resources/**")
                .addResourceLocations("/resources/", "classpath:/static/");
    }
}
```

Interview Tip:
A concise interview answer is:

"I override addResourceHandlers in a WebMvcConfigurer to map a URL pattern like /resources/** to physical locations such as classpath:/static/. That tells Spring MVC to serve those requests directly as static files instead of routing them through a controller, and I can add cache headers there too."