doubt about superclass reference and subclass object

class superclass
{
p.bark()
}
class subclass extends superclass
{
p.bark
}
{p.s.v.m()
superclass refvar = new subclass();
p.bark();
}

Now my questions 1.Why is necessary for parent to have a method in this case whether child have it or not? i am told that at compile time as reference variable is of superclass so compiler checks for this method in superclass at compile time, correct me if i am wrong anywhere.... 2.when compiler reads p.bark() where does it go next (i know child method overrides but i want to know that first it goes to superclass method or subclass and WHY?) 3.why subclass needs to have a access modifier of wider scope?