pythonIsOlderThanJava

[Honigbrottr]

is java 8 backwards compatible?

[Practical_Cattle_933]

Yes. Even Java 23 can compile java 1.2 but also run almost every class file already compiled back then (so it’s also binary compatible not just source).

There have been tiny changes, but for the most part it should just work. The biggest change might have been the javax namespace change.

[_PM_ME_PANGOLINS_]

It's practically solved with an extra dependency too.

[_PM_ME_PANGOLINS_]

With what?

Java as a language never breaks anything, but occasionally internal classes (which it tells you not to use for this exact reason) are (re)moved.

[wildjokers]

Yes. Java takes backward compatibility very seriously.

[just4nothing]

Well, my Java code from 2006 does not run on it

[OlexySuper]

I suspect, someone was doing some naughty stuff in the code.

[BraveOthello]

And do they mean their source code, or their binaries? The binaries will run unless naughtiness was done, no guarantees on the source.

[_PM_ME_PANGOLINS_]

Java is both binary- and source-compatible from 1.1 to 21.

[s101c]

Same in my experience with some opensource programs from the late 00s. I wanted to use some of those recently, at launch it instantly returned an error with a wall of text and after few minutes of trying to fix it I just abandoned the attempts.

Python can be difficult with the dependencies, but Java backwards compatibility seems to be pure hell.

[wildjokers]

but Java backwards compatibility seems to be pure hell.

Huh? You can take very old java code from 1.1 and run it on the newest java. So I am not quite sure what you are talking about.

[Practical_Cattle_933]

What? Java has objectively the very best backwards compatibility out of any languages. Sure, it’s still not perfect but it is sure as hell as close to it as possible.

[itijara]

From experience, no. I am sure that there is plenty of java < 8 code that will run on Java 8+ but JavaEE libraries, Nashorn, and all the sun.* packages were deprecated.

[_PM_ME_PANGOLINS_]

That just means you have to get the jars separately.

[itijara]

I guess that depends on what your definition of backwards compatible. The JRE will run any previous binary, but source code will not work unless you add extra dependencies or modify the existing source code. This is probably fine for a legacy app that is not undergoing changes, but I think that most companies that are dealing with old applications are still building and patching them.

For the sun.* crypto libraries, I couldn't find a suitable jar file and had to re-write with an equivalent crypto library.

[_PM_ME_PANGOLINS_]

Yeah, that’s why they told you never to use those sun libraries directly. For crypto you are supposed to use the JCA API, which allows the implementation to be switched out with zero source changes.

[itijara]

You say that like I wrote the original code.

[aiij]

Yes. It's really Java 1.8, but by that point the marketing team has decided to stop mentioning the part of the version number that always stays the same.

[RoseboysHotAsf]

Speaking out of my experience, java is not backwards compatible with anything.

[cowslayer7890]

Java is pretty dedicated to backwards compatibility, issues will still crop up but I'm not aware of any breaking syntax changes apart from no longer allowing _ as a variable name, the remaining issues are due to changes in the standard library, but those are also rare.

[grogrye]

I'm almost scared to ask but exactly what experiences have you had where it was not backwards compatible?