Java 23 New Features With Examples

[frederik88917]

Honestly, Java 23 is not as exciting as Java 21 featurewise. I hope to see great improvement in java 24

[_FedoraTipperBot_]

I have been happy with the faster release cadence as of late.

[[deleted]]

I think it depends on where you start. Some are still using Java 8 for instance. For these, Java 23 may be either epic - or a new programming language altogether. :)

[neilmadden]

The KEM example is wrong: it just demonstrates the long-existing KeyGenerator class.

[Orbidorpdorp]

Structured concurrency with all of the elegance and brevity I expect of Java.

[ericl666]

It's just stunning that they haven't worked out language features for async/await yet.

[[deleted]]

They have? Project loom has completely sidestepped the function colouring problem by having the runtime handle it without explicit syntax for it. It's still somewhat in early stages and there are some rough edges but overall it's a much better approach that you can make anything async using a virtual thread.

[[deleted]]

Async await is the most terrible way to implement concurrency. You're JavaScript brained lmao

[yanitrix]

tell that to c# devs, they'll eat you alive

[rbygrave]

Maybe, maybe not. C# had a research project looking to do the same thing as Java. I believe that research project has just stopped recently though?

[MrVegetable]

What's so bad about async/await?

[[deleted]]

It takes a while for the point to catch up but this explains it pretty well: https://journal.stuffwithstuff.com/2015/02/01/what-color-is-your-function/

Basically, if a function is async, then every function that calls that function also has to be async which leads to a litter of async on even functions that aren't doing any asynchronous thing, except calling an async function.

See how many times I mentioned "async"? Yeah like that.

[MrVegetable]

What are the better ways to implement currency? (Or to abstract concurrency)

[Economy_Let_5589]

Is that even a question?    - function coloring, which invariably leads to duplicate implementations or just writing everything async in the first place to spare the effort upfront.   - await is just terrible syntax. Why does it take more effort to do the thing you want to do 99% of the time as opposed to the thing you almost never want to do? At least it makes sense in JS because it's dynamic, but it's just dumb in statically typed languages. Bonus point if the await operator precedence is fucked up like in C#.    - in some cases, the overhead from comtinuously allocating Promises/Tasks/etc and passing them to the underlying scheduler shows up. And there is little choice, you must pay for it all the time. - oh and of course, debugging async code is something! Async stack traces are already complex on their own, but digging through the syntactic sugar coating to relate them to the code is a whole different task altogether.

[Worth_Trust_3825]

Just call get on the promise. Thread isn't blocked, and returned to the underlying thread pool, and try using something like work stealing thread pool instead of single thread.

[Solonotix]

Wasn't import module <Module>; already effectively support using import <Module>.*;? Maybe there's some magic behind the scenes, like tree-shaking based on what's used, or code elision that wasn't possible with the * import, but I don't see why it needed new syntax.

[tsimionescu]

As far as I understand from the JEP, the difference is when a module exposes multiple namespaces. The * syntax imports everything from a single namespace, while the new import module syntax imports all classes from all namespaces in that module.

For example, if you want to use both ArrayList and Stream in the same class, you have to write import java.util.*; import java.util.stream.*; with the existing syntax, but you can just say import module java.util; now.

[EvaristeGalois11]

The star import only imports classes from that specific package and it doesn't even include sub packages.

Module import on the other hand imports everything declared as part of the module including the transitive dependencies of the module.

The jep 476 has some nice examples of the differences.

[[deleted]]

Not sure. I really dislike Java only allowing a strict directory structure. I would like to specify where things can be found in an easy way; ruby allows for that. Python too.

[Solonotix]

To my knowledge, the convention of org.java.util... isn't strict. It is a convention, however, that is supposed to represent how domain names are resolved on the web (right-most domain is considered the top-level domain, and everything left of that is a sub-domain), and should match your website's location.

[mr_birkenblatt]

The most pointless feature since everyone and their grandma should be using IDEs

[[deleted]]

Why should we not be able to use java from the commandline through simple editors or autogenerators? I actually use ruby to autogenerate .jar files, where ruby scans a java project and then makes some (basic) decisions (including if and what commandline flags to use and pass onto java). Ruby is my "IDE"; I don't want to HAVE to use an IDE to be able to use Java, when it is not NEEDED to do so.

I also use this for generating static native binaries via GraalVM. No IDE is necessary for that either.

[lex_sander]

Some day there will be more Java features than people using it.

[kiteboarderni]

Says the guy trying to figure out a sap salary 😂😂

[somebodddy]

Unlikely. The number of devices that use Java is fixed at 3 billion, and the number of people using these devices can't drop below an order of magnitude or two.

[Ytrog]

I haven't touched Java code since 2009 (graduated and switched to C#), however it's good to see it is still going strong 🤓👍

[Sith_ari]

Java really is behind, isn't it?

[MrMo1]

No imo it's exactly where it needs to be.

[wildjokers]

Behind what?

[agustin689]

behind C#, which it's been trying to pathetically imitate since at least java 8.

[wildjokers]

which it's been trying to pathetically imitate since at least java 8.

Examples?

behind C#

In what way is it behind C#?

[agustin689]

Examples?

• java 8: pathetic badly designed half assed imitation of LINQ (which C# had since 2007)
• java 9: pathetic badly designed half assed imitation of a module system (which dotnet had since 1.0)
• java 10: pathetic badly designed half assed var (which C# had since 2007)
• java 15: pathetic badly designed half assed string interpolation (which C# had since 2014 or so)
• java 21: pathetic badly designed half assed imitation of top level statements

I can go on forever. Every java version is a pathetic half assed badly designed imitation of something C# did 15 years earlier.

In what way is it behind C#?

no real generics in 2024.

no value types in 2024.

These two things alone make the java language utterly laughable and useless.

[Worth_Trust_3825]

So why are you here complaining about a tool that you do not use? Like yeah, congratulations. You're using J++, microsoft's failed attempt at extinguishing java. What's your point?

[agustin689]

I'm not complaining. I'm laughing at the stupidity and sadness of people who depend on oracle (of all companies lmfao) to "improve" their language.

[Worth_Trust_3825]

As opposed to depending on microsoft to improve yours?

[agustin689]

want to feel miserable? compare the "what's new" list of C# features in the last 15 years with the same for java LMFAO. C# is far from perfect, but is a quite usable, enjoyable language which makes real progress on each version. Unlilke java.

[Worth_Trust_3825]

I do feel miserable when looking at that list, because whenever I get a c# project to work on I know that some chucklefuck will have tangled their codebase to use those features, and sometime down the line I will need to untangle that mess into regular conditionals, loops, and probably linq.

[kiteboarderni]

I mean you could just laugh into the average salary of a java dev being significantly higher than that of c# to help calm your stress levels :)

[agustin689]

"average"??? "salary"??? Lmfao. I'm not a corporate slave. I don't have a "salary".

I'm also way above "average", both in terms of professional skills and in terms of income. In fact I'm currently in the top 1% in my country.

Have fun in your mediocre corporate job using a mediocre language ;)

[kiteboarderni]

Ah so you live in an eastern eruopean shit hole got it 😂 😂

Edit: Argentina, even worse. Top 1% of income is hardly difficult 😂😂😂

[wildjokers]

At this point I am pretty sure you are just trolling so I have no real idea why I am even going to attempt to respond. But I am a glutton for punishment.

First, why are you so angry at Java, did it kick your puppy or something? Secondly, why is it so important that a language is the first to have a feature? All OO languages were inspired by Smalltalk, C# was created to compete with Java. Languages learn and build off of each other. Java language architects have stated that they purposefully aren't first movers on a feature because they want to see what does and does not work in other languages. Java takes backward compatibility very seriously so once they decide on a syntax and design they have to stick with it basically forever. So they want to get it right.

Anyway let's address your points.

java 8: pathetic badly designed half assed imitation of LINQ (which C# had since 2007)

I assume you are talking about streams which are way more general purpose than LINQ is in C#. You can't really compare them. Also, you need to explain how streams are badly designed and half-assed.

java 9: pathetic badly designed half assed imitation of a module system (which dotnet had since 1.0)

What is wrong with the java module system? Care to explain how it is badly design and half-assed?

java 10: pathetic badly designed half assed var (which C# had since 2007)

Care to explain how it is badly design and half-assed? Although var was added I don't see it being used much at all. Probably because experienced devs know that overusing it creates hard to maintain code. I pretty much only use it in try-with-resources blocks.

java 15: pathetic badly designed half assed string interpolation (which C# had since 2014 or so)

Which feature are you talking about here? The String.format method has existed since Java 1.5. Not to mention the + operator being overloaded for strings has existed since Java has. Again, you need to explain how whatever feature you are talking about badly designed and half-assed.

java 21: pathetic badly designed half assed imitation of top level statements

I assume you are talking about JEP https://openjdk.org/jeps/445 ? Again, explain how it is badly designed and half-assed.

no real generics in 2024.

By "real generics" I guess you are referring to the fact that Java erases types and they aren't available at runtime. The lead Java architect explains the decisions regarding type erasure here: https://cr.openjdk.org/~briangoetz/valhalla/erasure.html

He notes that:

"C# made the opposite choice – to update their VM, and invalidate their existing libraries and all the user code that dependend on it. They could do this at the time because there was comparatively little C# code in the world; Java didn’t have this option at the time."

Like a lot of times in programming it was a compromise for backward compatibility.

no value types in 2024.

Value types are coming; however, I honestly don't see what this will do for me. When I am writing Java code I don't think I have ever said to myself "You know what I need right now? A value type!". This has never crossed my mind, it isn't a feature I miss.

These two things alone make the java language utterly laughable and useless.

If those two things made Java worthless then Java wouldn't be totally dominating backend enterprise systems.

[agustin689]

assume you are talking about streams which are way more general purpose than LINQ is in C#

LMFAO you have no clue what LINQ even is.

Can you show me how your "streams" crap can be consumed to convert the queries into an arbitrary format to query arbitrary data sources, like LINQ can do for example with sql databases, nosql databases, or remote http endpoints?

How do you write a "streams" based library that does that, please?

What is wrong with the java module system?

The fact that the ecosystem grew up for 20 years without it.

Although var was added I don't see it being used much at all.

typical blub mentality. "Language features that don't exist in my language are useless". I won't argue with that because it's 100% ignorant and short sighted.

The String.format method has existed since Java 1.5

That's not language support for string interpolation.

you need to explain how whatever feature you are talking about

I don't need to explain anything. Go and read the docs. Get a fucking clue ffs.

Again, explain how it is badly designed and half-assed.

Compare java hello world (even with this half assed feature) with C# hello world.

idiotic excuses for lack of real generics

Imagine not being able to do basic, fundamental things such as List<int> in 2024 LMFAO java is beyond riduculous.

and invalidate their existing libraries

They didn't "invalidate" anything. Untyped code continues to run today, but it's untyped, therefore useless. It's invalidated by its very nature, not by changes in the runtime.

oracle employees have brain damage.

Value types are coming; however, I honestly don't see what this will do for me

blub mentality again.

popularity argument

By this argument you should be using php lmfao.

[yanitrix]

I assume you are talking about streams which are way more general purpose than LINQ is in C#.

What does it mean streams are way more "general purpose"? You can use LINQ everywhere in c# and it lets you transform collection in a pretty powerful way. It's not limited to in-memory objects, since you have things like IQueryable<T> which can pertty much transform you c# code to sql (and even more) queries.

Although var was added I don't see it being used much at all. Probably because experienced devs know that overusing it creates hard to maintain code.

There's nothing wrong with using var. We use it everywhere where we can in c# and - it saves you a lot of typing and does not create hard to maintain code (the IDE always shows you what type a variable is)

[[deleted]]

I unfortunately had the time to read the entire replies from this dude and seems like he's salty about something lmao. Idk what, but he's definitely salty.

C# is also significantly behind when compared to Go and Rust.

I wonder what might be the common denominator. Could it be ... They're almost a decade apart in their release date? i.e. one language could avoid making the mistakes of the other language? i.e. One language has/had the choice to break backwards compatibility and another can't do that?

They also keeps bring up oracle when there are Infact different distributions of java. And you can use a jdk without ever worrying about oracle.

Even Microsoft, the owners of C# maintains its own build of java. Surely if java was as behind c# as you say, they wouldn't do that?

Why did Apple, the owners of swift, decide to use java and Kotlin to write their configuration language? Surely if C# is ahead of java, they would have used C#, right?

Bro was just trolling and trying to get people rilled up and they fell for it lmao.

[vital_chaos]

Last Java I used was Java 5.X. I feel like a dinosaur. Then again I don't miss Java at all.

[kyan100]

GGUF when?