Dev Idea: compare object types using instanceof instead of class names

[bencomp]

Overview of the Feature Request
This is a simple idea relating to code style and type safety: if you want to test whether an object is of a certain type, use the Java keyword instanceof.

What kind of user is the feature intended for?

Developers.

What inspired the request?

A TODO comment asking if there was a better way to compare types.

What existing behavior do you want changed?

No application behaviour should be changed; this is a small suggestion for refactoring. (I don't think this will be introduced again, though it's good to keep an eye out for developer behaviour.)

Any brand new behavior do you want to add to Dataverse?

No.

Any related open or closed issues to this feature request?

Well, #775 and #3950 are related to code style.

I already suggested changes in PRs #9010 and #9014.

[bencomp]

SonarLint and Sonarcloud also suggest to compare types using instanceof, so this may be another reason for #9846