response.setHeader("Content-Type", "application/json");
response.setHeader("Cache-Control", "max-age=3600");
response.setHeader("X-MyApp-Version", "1.2.3");This will add a custom header to the response, which can be useful for tracking the version of your app or other metadata. All of these examples use the `javax.servlet.http` package, which is part of the Java Servlet API. This API is used to build server-side web applications in Java.