Almost at the end of main

[aaime]

Hi @groldan while I kept on having a look at the errorprone situation, I fixed a few things. Approach:

• Mass fix the whole Codebase if IntelliJ could do it
• Ignore the warning otherwise, leaving each suppression for a rainy day (I typically fare better if I handle one at a time, it's always the same thing to fix).

Not sure if you'll find it useful or not, take it as is, throw it away, cherry pick parts you like... do as you see fit! 😄

Checklist

• I have read the contribution guidelines.
• I have sent a Contribution Licence Agreement (not required for small changes, e.g., fixing typos in documentation).
• First PR targets the main branch (backports managed later; ignore for branch specific issues).
• Avoid Java 9+ split packages.
• All the build checks are green (see automated QA checks).

For core and extension modules:

• New unit tests have been added covering the changes.
• Documentation has been updated (if change is visible to end users).
• There is an issue in GeoTools Jira (except for changes not visible to end users).
• Commit message(s) must be in the form [GEOT-XYZW] Title of the Jira ticket.
• Bug fixes and small new features are presented as a single commit.
• The commit targets a single objective (if multiple focuses cannot be avoided, each one is in its own commit, and has a separate ticket describing it).