It's still their project and the Oracle Contributor Agreement means they get to asset joint ownership of your contributions.
That's broadly the point of CLAs, but for a beefy project like OpenJDK with so much shared code baked deep into enterprise deployment, Oracle will feel it's critical they can pull freely given code into the depths of their closed Java builds.
It's their project. It does absolutely block contributions (employers are unhappy sacrificing their engineering output to Oracle). If you don't like it, fork it.
So TL;DR I'm right to be skeptical of everything Java because even OpenJDK is pretty much owned and controlled by Oracle? Good to know. I'll keep avoiding it like the plague then, with slightly more confidence:
Not really. OpenJDK is exactly what OpenJDK is, and there are plenty of builds provided by other vendors who have nothing to do with Oracle. All Oracle "owning" it really means is that they basically have unilateral ability to make changes to Java[1], where said changes will be reflected in their official binary releases. And they charge for their releases (and have some auditing / licensing terms which many find off-putting) which is only important if it's really important for you to use an Official Oracle Build for some reason, as opposed to Eclipse Temurin, Amazon Corretto, BellSoft Liberica, Red Hat's build, etc.
Personally I just use the OpenJDK builds provided by my linux distro and never give it a second thought.
[1]: And so far, Oracle haven't shown much, if any, propensity for abusing their control of Java. There's a process and they seem to mostly stick to it.
Oracle might only accept upstream contributions but OpenJDK is GPL2, so anyone can host their fork of OpenJDK with whatever GPL2-licensed patches they like, regardless of the OCA/CLA being signed. Indeed there are enough distributions of OpenJDK that there's a site for picking which is best for you. I can't really speak to how current that information is, or how good it is, but it exists: https://whichjdk.com/
But yes, you might be right to be suspect of Java as a whole if this is how they treat contributors.
It's worth noting that many larger open source projects have contributor agreements to strengthen their rights for redistribution that a standard license might not cover. What if they want to change the license? They don't want to be hamstrung by a million contributions. Moral rights are something you often see. And severability might also be a concern. Some like the OCA are worse than others. The Python one is pretty good because it limits any future relicensing to open source. https://www.python.org/psf/contrib/contrib-form/
That's broadly the point of CLAs, but for a beefy project like OpenJDK with so much shared code baked deep into enterprise deployment, Oracle will feel it's critical they can pull freely given code into the depths of their closed Java builds.
It's their project. It does absolutely block contributions (employers are unhappy sacrificing their engineering output to Oracle). If you don't like it, fork it.