Custom error page
When a user requests a non-existing page, the servlet container (Tomcat) or application server displays a 404 error page and returns the 404 error code. You can configure what happens in the case of a 404 directly in the web.xml configuration file in the container.
A common solution is to create a custom error page that looks like the rest of your site, tells the visitor in clear terms that the page was not found, and provides some alternative ways to continue such as navigation and a search box.
web.xml
<error-page>
<error-code>404</error-code>
<location>/error/404.html</location>
</error-page> Additional error codes
404 is, of course, not the only error code. You can set up custom error pages for any error code using the same approach.
See Site aware exception handling in Magnolia CMS for tips on how to do that.