Strange o/p.Polymorphism in Overrided method?

[Micheal John]

package com;
class A3{
   void m1(A3 a){
System.out.print("A");
   }
}
 
class B3 extends A3{
   void m1(B3 b){
System.out.print("B");
   }
 
}
 
class C3 extends B3{
   void m1(C3 c){
System.out.print("C");
   }
}
 
class D3{
public static void main(String args[]){
A3 a3 = new A3();
B3 b3 = new B3();
C3 c3 = new C3();
A3 a4 = new C3();
a4.m1(a3);
a4.m1(b3);
a4.m1(c3);
 
}
 
}

For the above pgm, how the o/p is: AAA

In all the three classes m1 has been overrided and polymorphism will come to play. so the below line
A3 a4 = new C3();
ref var is A3 and resolved at compile time, but while run time it has to call the C3 object's m1() only.. how it's calling A3 object's m1()?

[Keith Lynn]

Notice there is no overriding because the methods do not have the same signatures.

[Satish Kota]

You are not overriding you are overloading the methods. And which methods to be called will be determined by the referenced type