GH-10083: Migrate ZeroMQ module to Jspecify

[anthologia]

Related to: #10083

Changes:

• Replaced org.springframework.lang.Nullable with org.jspecify.annotations.Nullable

Should I create separate PRs for each module?

[artembilan]

Fixes: #10083

Is not correct in the PR since it does not fully fix the whole issue.
Please, don't use it for this kind of PRs again.
Better like Related to:

Should I create separate PRs for each module?

Yes, please.
That will be easier for us to review.

Thanks

[artembilan]

I'm not sure if this was automated, but can we also look into migrating those package-info.java files in this module to the org.jspecify.annotations.NullMarked instead of those deprecated over there?
Then it would be great to run gradlew :spring-integration-zeromq:check and see if your change passes NullAway.

Thanks

[artembilan]

I know the org.jspecify.annotations.NullMarked is a phase 2 in our issue roadmap, but that is OK to do that for such a small module in one go, so we would know where we are for the rest of the project.

Thanks

[artembilan]

We have just merged one for Camel module: b07d04f.

Feel free to follow its experience!