Jodd – The Unbearable Lightness of Java

Post by dopidopHN » Tue, Jan 18, 2022, 2:42 AM UTC

spuz wrote: post #5

I wonder if someone can recommend a lightweight http server library? I like Javalin but it's based on Jetty which is a fully JavaEE compliant framework and includes support for things like OSGI which I don't need. With the whole Log4j situation, I'm re-evaluating some the libraries I've previously relied on.

Post by WatchDog » Tue, Jan 18, 2022, 2:47 AM UTC

guelo wrote: post #48

WatchDog wrote: post #30

Earlier quoted context omitted.

You can do DI without a framework. If you write classes with final fields, with a constrcutor that takes the class' dependencies,and don't use static fields to hold mutable data. You are doing DI. Just call `new` yourself, instead of having the framework do it for you.

Is what you're thinking of equivalent to deep argument passing? I've seen it done where you pass around a global Factory object that can provide dependencies. It's basically rudimentary DIY DI.

    public static void main(String[] args) {
        MyConfig config = readConfigFile();
        DatabaseConnection dbConn = new DatabaseConnection(config.dbHost(), config.dbPort());
        UserDao userDao = new UserDao(dbConn);
        UserController userController = new UserController(userDao);
        List controllers = List.of(userController);
        WebServer webServer = new WebServer(config.listenPort(), controllers);
        webServer.runAndBlock();
    }

Post by yencabulator » Tue, Jan 18, 2022, 2:57 AM UTC

stickfigure wrote: post #49

WatchDog wrote: post #30

Earlier quoted context omitted.

You can do DI without a framework. If you write classes with final fields, with a constrcutor that takes the class' dependencies,and don't use static fields to hold mutable data. You are doing DI. Just call `new` yourself, instead of having the framework do it for you.

When you have lots of things-that-create-things-that-create-things, this gets tedious really fast. DI frameworks exist because they result in a lot less code that does nothing but pass dependences along. This reminds me of SQL/ORM debate. "Just use SQL!" Sure, until you get tired of typing the same SQL over and over and realize you can cut out most of that crap by adding an ORM.

Post by otterley » Tue, Jan 18, 2022, 2:58 AM UTC

geodel wrote: post #41

benhoyt wrote: post #25

Earlier quoted context omitted.

Why do "static references become a tangled mess"? In my (limited) experience with runtime DI libraries (albeit in Go) they turn clear, IDE- and debugging-friendly code where the compiler tells you at compile time if you got it wrong ... into a hard-to-debug magical soup. With static, using-the-language dependency injection, isn't the question of "how does ABC component get access to DEF?" answerable with the normal I…

> but I must be missing something here. As a Java developer for all my career here is my take. In Java world there is this cultish cottage industry of "frameworks" for all sorts of work. Most Java developers are not expected to write plain code with JDK standard + some external libraries. Creating an object via "new Obj()" might cause programing universe to collapse so DI framework is must for enterprise Java develop…

Post by mycall » Tue, Jan 18, 2022, 3:02 AM UTC

WatchDog wrote: post #16

winrid wrote: post #10

Earlier quoted context omitted.

EDIT - it seems maybe I was wrong here Netty copies the response body when sending to each client, so it's not as lightweight as I've found. For streaming large response bodies, it does not work well. I haven't found a good Java alternative yet (probably will switch to C++ and uWS...)

Netty core is about as close to the metal as networking gets on the JVM. It's abstractions are built over a zero-copy capable byte buffer, and there is generally a lot of care taken to avoid copying where possible. I haven't used the websocket codec, but I'm sure the maintainers would welcome a patch that removes unnecessary copying.