What Java class can I extend to?

Question

What Java class can I extend to so that I gain inheritance to treeTableView? How do I extend a class that is already extended?

I'm currently extending it using treeTableView.

The demo file shows this:

final TreeItem<User> root = new RecursiveTreeItem<User>(users, RecursiveTreeObject::getChildren);

This is what I tried working out, but it's not working:

final TreeItem<Patient> root = new Patient(patients, Patient::getChildren);

What do I do?

Answer 1

I extended the Person superclass to RecursiveTreeObject. Through inheritance it worked.