Confusion about superclass references and subclass objects

I have some questions about this code:

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

1. Why is it necessary for the parent to have a method in this case, whether the child has it or not? I am told that at compile time the reference variable is of superclass type, so the compiler checks for this method in the superclass at compile time; is that accurate?




2. When the compiler reads p.bark(), how does it know where to go next? I know the child method overrides it, but I want to know that first it goes to the superclass method or subclass, and why.




3. Why does the subclass need to have an access modifier of wider scope?

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