Yeah, it's not "constructor class", it's "class constructor" - meaning a special method used to construct (initialize) a class instance as it's being created.
Variables can be defined for the class (either as member or static variables), as parameters of method definitions, or withing method code blocks.
The qualifiers "public", "private" and "" (no explicit, meaning package-level) apply only to class variables. The other types exist only when their associated code is executed and live only on the
thread stack for that code, being discaarded when the code or code block terminates.
You're never really "creating" variables, anyway. You just define them and then assign values to them. Sometimes you create an instance of a class, and assign a reference to that instance to a variable. That's about as close as you can get to "creating" a variable. Some other languages do allow you to "create" a new variable in their "classes", like Python and JavaScript, but that's not how Java works.