[kaashif]

> when Java 8 added a lot of (well-needed) new syntax, it felt like that was an ideal opportunity to add ADTs and pattern matching

Well at least Java does now (as of Java 21) have pattern matching (including nested record destructuring) and sealed classes, which let you have decent sum types.

The one issue is that everything is nullable, but that's a wider Java issue.

[tombert]

Yeah, but the annoying part of Java is that people stick with old versions for a long time. Java 21 looks pretty great but most companies are still using Java 17, or even Java 11 still.

[cess11]

Some have even older Java versions in 'prod'. 6 is still alive in some places out there, because management refuses to pay for either upgrade, replacement or dismantling.

I have a mid-sized application I built on 17 that's used to deliver a particular project, really looking forward to finish the project so I get to move to 21 and refactor it with these new features and make it more general.

[tombert]

Oof, I didn't know that anyone still used Java 6 anywhere. I have to think that it's a potential security nightmare at this point isn't it?

[Tainnor]

It is. We run an old version of our application on Java 6. Apparently multiple people have tried to upgrade it in the past but it proved too difficult because it's using a bunch of completely obsolete technology with little available documentation that seems to randomly break when you upgrade even minor things.

The plan has been to gradually replace it with the new version of the software (which runs on Java 17), unfortunately this plan has been ongoing for 10 years and it's not gonna be done anytime soon.

Such are the sad realities of working on legacy code sometimes.

[cess11]

Absolutely, so you try to seal it in hermetically, only talk to it over a special message bus or something.

Sometimes the upgrade path from 6 onwards isn't as nice as it usually is from 8 up, especially if you built with some old undead libraries that require an heroic effort to understand well enough to reimplement. Takes a very special organisation to divert some person-years to pull it off, and as some middle or other manager it's highly unlikely to catch you a new, better job even if it goes well.

[tombert]

It makes me sad, but I totally understand why someone would stay with Java 6, for the same reason that there's still COBOL stuff hanging around: the stuff "works" as is, upgrading is expensive, and some business person decided that the cost of the upgrade isn't worth it for the value they'd receive.

I do worry that there's "Y2K-esque" bugs hiding in Java 6 programs somewhere. I don't think java.util.date uses 32 bit integers for time so the 2038 problem probably won't be an issue, but I do wonder if there's other stuff hiding.

[cess11]

There might be some limit or bug like that in Java 6, but I think time stuff has been backported, so it'd likely be something else. I don't know enough about the JVM internals to speculate on whether the old ones were simpler and less likely to be defective, or not.

By now most types of issues ought to have popped up though, since it was so widely used for such a long time.

[Tainnor]

Cryptography is kind of an issue . Certain protocols that by now are expected aren't supported by Java 6.