Polymorphism with Static Methods

Polymorphism with Static Methods

1. Shocking Truth (beginner!)

Static methods DON'T override — they hide (like fields!). Which version runs depends on REFERENCE (not object!). No runtime magic for static!

2. Proof Code (compare with instance!)

class Animal {
    static void show() { System.out.println("Animal static"); }
    void sound() { System.out.println("Animal sound"); }
}
class Dog extends Animal {
    static void show() { System.out.println("Dog static"); } // HIDES (not override!)
    @Override void sound() { System.out.println("bark"); }   // OVERRIDES!
}
Animal a = new Dog();
a.show();  // Animal static! (reference wins — NO polymorphism!)
a.sound(); // bark! (object wins — true polymorphism!)
// @Override on static → ERROR! (proves no override!)

3. Rules (exam list!)

	Static method	Instance method
Child same signature	hides (reference!)	overrides (object!)
@Override	ERROR!	OK!
Call style	ClassName.m() (preferred!)	obj.m()

4. Why? (one line for viva!)

Static belongs to class (no this/object!) — JVM can't dispatch by object. Compiler binds by reference at compile time.

5. Exam Points

• Static-hide vs instance-override trace — 5-7 marks, very frequent.
• @Override error on static — 3 marks, favourite proof.