A a = new A and B b = new B and a=b is that mean that's A a = new B ???

Answer 1

Maybe, try it in the editor.

Answer 2

Works if B extends A.

Answer 3

Also works if both A and B are extended from the same parent or at least have a common ancestor. On some level it will work (but not necessarily the way you want it to) because all classes inherit from Object.

Answer 4

yes is important to extends A thanks