That’s indeed true, but it wasn’t a constraint so I thought it may be of interest to post it :D should have added a note regarding that though, but I can no longer edit.
Go's net/http is essentially the only used Go HTTP(S) server. It is often wrapped with other libs to add things like request routing, but it is always used as the actual HTTP implementation. Not sure why you're saying its purpose is "hello world".
The Java one is not usable in anything beyond hello world, and is explicitly not intended to be.
As someone maintaining a pretty large networking industry proprietary app based entirely on net/http in terms of any kind of HTTP communication, I feel like I can easily tell you are wildly exaggerating. Admin consoles and enterprise connectors are entirely irrelevant to many uses of an HTTP server. Hell, even Kubernetes' API server is built using net/http.
Given that it was only added in Java 18 and it is a simple static file server (no way to run custom code when serving a URL), I don't think it's in any way widely used at the moment.
Edit: or will ever be. It is definitely explicitly not an equivalent of go's net/http. Indeed, there is probably never going to be an equivalent of net/http in the Java stdlib (since they prefer to rely on the user choosing one of the existing server frameworks, such as Jetty).
Yes, per the JEP that was linked, it is only intended as a toy server for quick example code, essentially:
> Provide a command-line tool to start a minimal web server that serves static files only. No CGI or servlet-like functionality is available. This tool will be useful for prototyping, ad-hoc coding, and testing purposes, particularly in educational contexts.
> It is not a goal to provide a feature-rich or commercial-grade server. Far better alternatives exist in the form of server frameworks (e.g., Jetty, Netty, and Grizzly) and production servers (e.g., Apache Tomcat, Apache httpd, and NGINX).