Why is method which accepts sub-class object doesn't recognize object of sub-class with the reference of the superclass?

Question

I have two classes(Vector and Stack) the one extends another.Resourse class has four methods.

When I pass a object of sub-class with reference of super-class it calls method that accepts super-class object not sub-class?Why does it happen?

 class Vector{
    
    }
    class Stack extends Vector{
    
    }
    public class Resources {
          public static void getIntS(Vector vector){
              System.out.println("Int of Vector");
          }
        public static void getIntS(Stack stack){
            System.out.println("Int of Stack");
        }
        public  void getInt(Vector vector){
            System.out.println("Int of Vector(Not static)");
        }
        public  void getInt(Stack stack){
            System.out.println("Int of Stack(Not static)");
        }
    
        public static void main(String[] args){
            Resources resources = new Resources();
            Vector vector = new Stack();
            Stack stack = new Stack();
            getIntS(vector);
            getIntS(stack);
            resources.getInt(vector);
            resources.getInt(stack);
        }
    }

Output :

Int of Vector
Int of Stack
Int of Vector(Not static)
Int of Stack(Not static)