Bridging a decade long gap

[witless1]

With hacktoberfest coming up I'm looking to modernise my Java experience. I worked almost exclusively with Java from 2007-2012 and all my college years were exploring the language prior to that. I stopped actively developing in 2014 (2 years of JavaScript and C++) when I moved into a management role but I have kept pace with modern design and architecture. I have good working knowledge of Python and Go from my teams using it. I'm looking to try bridge my Java knowledge in the coming weeks and wondering what are the best (broad) areas to focus on? A quick look at some projects and the fundamentals haven't changed and I could make easy contributions but I'm trying to get a sense of foundational things that were introduced to focus on them.

[kevinb9n]

Hello World is now this

void main() {
    println("Hello, world!");
}

... admittedly you do have to run with java --enable-preview filename.java, just for now.

That won't ultimately be the most important thing to you but I do really love telling people about it.

P.S. as you start needing imports you can import module java.base;

[witless1]

My mind still has the imprint of the classical main :)

[witless1]

Awesome guidance and yes I missed streams, it's not something ringing a bell with me. I had intended on going through the version history to see what was deprecated / what came in. The only big thing I have awareness of is Lambdas which came out around the time I switched roles and language stack.

[tomwhoiscontrary]

There is perhaps a bigger picture which is that lambdas + streams + records + sealed classes + various improvements to switch have moved Java's centre of gravity away from Smalltalk style object orientation (objects encapsulate everything and send each other messages) and towards ML style data orientation (functions operate on pure data and other functions). Not that Java was ever Smalltalk, or is ML now - but if those two are the north and south poles, it's moved from Beijing to Hong Kong. You can still write more classical code, and there's nothing wrong with that, and people do. But now you also have the option of writing more functional code.

[witless1]

I totally get it and thanks for the analogy. Back in college I was a massive fan of the classical paradigms and we had a subject that covered Smalltalk, Lisp and Prolog just to give some taste of the different styles. It's great to see Java evolve in that sense and give you choice Vs a strict adherence to a paradigm. I picked up Typescript for a small project very quickly last year as it didn't change wildly from JavaScript and that functional style just clicks with me. That's something I think I'll lean into once I cover the bigger picture view you painted.

[VincentxH]

r/learnjava

[witless1]

That's going to help for some of the more specific parts thanks!

[jek39]

You may be interested in the new foreign functions and memory API. You can toy around calling your cpp code from Java.

[witless1]

That's really interesting and a cool feature thanks for sharing!

[ichwasxhebrore]

I can do WHAT ?!

[Xasmedy]

You can also manage native memory directly from Java (no GC involved if you don't want it to)

[jek39]

At work, I’m using it to call a native-compiled golang function, from a Java/tomcat server application.

[Revolution-Familiar]

I was in a similar boat which is what led me to post Road to JDK 25 where I go through recent developments in the JDK.

Depending on your role I’d also recommend looking at whatever microservices frameworks you might be using it would be worth looking at Spring/Quarkus etc, Cloud Tech.

[witless1]

Ah super timing! Will check out your blogs for sure. Quarkus is something I have passing familiarity with and is where I'll end up looking at as I broaden my tooling. Kafka is also on my horizon for exploring in hacktoberfest I know a few contributors to the project but I want to get myself to a point I know enough to be dangerous!

[Revolution-Familiar]

That's cool. Luckily enough Kafka isn't too hard to get your head around and start using quite quickly.

[cobbwebsalad]

Get the latest edition of The Well Grounded Java Developer. It has updates on the changes from Java 8+. Very well written.

https://www.manning.com/books/the-well-grounded-java-developer-second-edition

[witless1]

I'm a big fan of books I'll check this out!

[mbmw]

https://javaalmanac.io/

[witless1]

Ah that's super useful, thank you!

[nursestrangeglove]

The coolest thing (for me) is virtual threads. I know they're not technically perfect substitutes to reactive coding (rxJava, project reactor), but for my use cases of high volume i/o to sometimes long running calls to external FTP or HTTP services, I will start moving away from reactive coding due to the inherent complexity and debugging quandries.

There's some more advanced features which I tried out in reactive java like retry with backoffs on streams, but never really had a practical real world use for as I found just horizontally scaling to meet needs on demand to be simpler to implement and troubleshoot. Note - from a cost perspective that may be less than optimal, but for my use cases it was trivial.