"For Java, the latest one. Current latest java still runs 20 year old jars."
Not necessarily anymore. Many of the standard JVM features were removed in 11+ instances, so things like _some_ of the JVMs JMX APIs were removed for one reason or other. I'm not saying the removals weren't justified, simply clarifying that not all java applications written N years ago are still entirely supported.
> Current latest java still runs 20 year old jars.
Dude, I've been using Java since 1.2. Sure, all versions will try to "run" anything, but they'll do that with all sorts of slight differences and incompatibilities in behaviour - which make it effectively impractical for any serious program to run on anything but a small subset of tried and tested versions.
> The OS distributor
Careful what you wish for. Do you really want to hand Microsoft the power to decide which runtimes are allowed to run on Windows...?
Not necessarily anymore. Many of the standard JVM features were removed in 11+ instances, so things like _some_ of the JVMs JMX APIs were removed for one reason or other. I'm not saying the removals weren't justified, simply clarifying that not all java applications written N years ago are still entirely supported.