I speak from the experience of supervised the upgrade of thousands of services from JDK8 to JDK17
There’s few quirks added but:
1. JDK17 will happily run JDK8 code without any changes 2. Most of the issues I observed were due to project jigsaw (and were resolved by adding —add-opens as needed)
I would expect 17 > 21 upgrade to have basically no issues as an upgrade in place
I hate Java but backwards compatibility isn’t one of the reasons why I hate it
So companies either pay Oracle to maintain the old JDK8, or use something like Amazon Corretto. It's so bad that there are companies promising JDK8 support until 2031 at least.
And yeah, upgrades past 17 are easy.
Come on, that's absolutely not the reason behind. That just means that there are banks and such that still run goddamn windows XP completely firewalled off from the internet just because. Similarly, for some companies not touching that ancient codebase and just having it safely run worth the hassle and the money.
Java is the most backwards compatible language and it is not even a close competition.
It's amazing to have two contradicting sentences right next to each other.
In competitions consisting of Java, PHP and Python, I presume?