Joda-Beans VS project-loom-c5m

That means I don't forget about fields (as can happen if you're just doing `person.setX()` all the time). It's easy to see what is what when reading it. I can delete fields I don't want to initialize at the time. Yes, maybe immutable objects are the One True Way, but C# lets me choose (I can label properties with an initializer `init` rather than a setter `set` and then they're immutable).

Kotlin offers stuff like this too because it's really useful toward creating code that's easy to create and maintain. Go also lets you initialize structs in a similar fashion.

Java has come back to us a decade or more late with records. They're not bad, but they're only offering one thing. They don't cover what C#, Kotlin, Go, and other languages have offered for so long.

The annoying thing about Java is that it doesn't feel pragmatic a lot of the time. It feels like the language hates stealing ideas from others. It's Java: people steal ideas from Java, not the other way around. People do crazy things just to get POJOs including Immutables (http://immutables.github.io), AutoValue (https://github.com/google/auto/), Lombok (https://projectlombok.org), Joda Beans (https://www.joda.org/joda-beans/), and maybe more. They generate lots of code at compile time or do funky runtime stuff.

It just feels like Java misses the pragmatic stuff and still kinda doesn't want to handle that. I feel a bit silly harping on things like POJOs and setting data on a new object, but that's a big part of day-to-day stuff and it definitely pushes users away from Java towards languages that seem "better" simply because they don't have Java's oddly strong attachment to not offering simple value objects. Yes, again, records do something - but it feels like Java ignored how people are using Kotlin, Go, C#, and more and didn't go for something that would have been as widely applicable and pragmatic as it could have been.

Java has a lot of great stuff like great GCs (yes), lots of cool research, great performance, and Project Loom is really exciting. I just wish the language would lean a little more practical.

I know I've been talking about properties a bunch, but let's look at Java. Java Beans are terrible - so terrible that the community has a number of workarounds. Immutables (https://immutables.github.io) lets you generate builders, Lombok (https://projectlombok.org) has their annotations that do runtime and IDE magic, there's Joda-Beans (https://www.joda.org/joda-beans/), there's the new Java Records if you want immutable-only and non-compatibility with lots of libraries, there are people using Kotlin for their data classes and Java for other things... Properties are this simple thing that lets C# work with the whole getter/setter pattern without being horribly annoying - there's just this weird { get; set; } thing that I can ignore because I don't care.

It is not. Blocking IO (with some exceptions mentioned in the JEP) will automatically be translated by the runtime into non-blocking IO when it occurs on virtual threads, and no OS threads will be blocked. You can have a million threads blocking on a million sockets (obviously without creating a million OS threads): https://github.com/ebarlas/project-loom-c5m

You can't do that with thread pools. You could achieve that scalability with async code, but then observability tools will not be able to track the IO operations and who initiated them, but with virtual threads you'll see exactly what business operation is doing what IO and why.

That might change in JDK 21 (with virtual threads). See this https://github.com/ebarlas/project-loom-c5m . It achieve 5 million persistent connections (again depends on the server capacity and kernal tuning) using normal simple blocking code (https://github.com/ebarlas/project-loom-c5m/blob/main/src/main/java/loomtest/EchoServer.java) . It's a far better better programming model compared to JS async/await.