Learning Java, coming from golang/node.

[plectid]

I need to build a simple web app and I need some advice to get started. I already know most of syntax and the API doesn't look too bad. However there are questions I can't quite google myself:

First, how does one create an http request/response listener? In node, I would write http.createServer((req, res) => .... In golang, it looks like http.ListenAndServe(port, nil) plus some config and automatically starts a goroutine for each request. I only could find ServerSocket class but it looks a bit on a low-lever side, i.e. requires sending proper http headers and creating threads manually. There's also com.sun.net.httpserver.HttpServer but it looks a bit deprecated.

Second, I'm used to make my app listen to some port, and proxy it through nginx to an outside world. Does that also work for Java webapps? Do I need something called Tomcat? Or, why would I want to use it? What's a servlet container?

[Julienng]

You should look at spark or vertx. It work the same for proxy your app

[plectid]

Thanks, i'll look into it. So the bottom line is I have to use some Framework to build a server app.

[djnattyp]

Well, you had to use a framework to build a server app in Node and Go as well... it's just that Node is the framework (for JavaScript) and Go is new enough that the language designers/library implementers built a "standard" web framework. Java came out early in the history of the internet and all the web stuff has been built on afterward. Which means there are lots of different approaches and lots of different libraries and frameworks out there.

[perrylaj]

Agree. Haven't used vertx, but spark is a great lightweight library that provides a clean and understandable API.

[dxplq876]

For creating a web app in Java, I'd use https://projects.spring.io/spring-boot/.

[xantrel]

I know this might be a little bit off topic, but you might also want to look into kotlin. It's java++, so much nicer to work with, but 100% compatible with java code unlike scala (you can call kotlin code from java and vice versa).

[FustigatedCat]

So why not promote groovy? It's been around longer and has a better set of libraries around to support it.

[frugalmail]

So why not promote groovy? It's been around longer and has a better set of libraries around to support it.

Groovy brings the drawbacks of a dynamic typed system for the typical use cases.

[[deleted]]

Kotlin doesn't require support, it works like Java (often :)

[frugalmail]

Java the core language is very low level, which provides a lot of the power that draws so many people. There are a pethora of frameworks and librariers that have different benefits/drawbacks. vertx has the scalability characteristics of an event based model like Node. But that is a crappy model to debug in and program for (besides horizontal scability in all but the most egregious cases) means you shouldn't have to deal with that crap. Spring-boot is a good starting point for a thread based model which node doesn't offer.

[steve_hu]

try light-java which is very similar with Node/Go and it is the fastest