overriding

[srinivas sridaragaddi]

 class A{
void m1(A a){System.out.println("a");
}
}
class B extends A{
void m1(B b){System.out.println("b");
}
}
class C extends B{
void m1(C c){System.out.println("c");
}
}
 
public class Test3 extends C{
void m1(Test3 d){System.out.println("d");
}
 
public static void main(String args[]){
A a1=new A();
B b1=new B();
C c1=new C();
Test3 d1=new Test3();
d1.m1(a1);
d1.m1(b1);
d1.m1(c1);
}
}   

output:abc


can somebody explain me the output. i was thinking its a compiler error as
d1.m1(a1) where a1 is d1 fails i.e is-a test fails.

[suresh mulagala]

a1 is the superclass and you are overriding m1, so d1.m1(a1) is valid and prints "a" and so on and so forth...

here it is evaluating to A's method because you are passing in an instance of A().

[Sarah Jorden]

Is it 'overriding'? I think its 'overloading'.
[ October 03, 2007: Message edited by: Sarah Jorden ]

[Burkhard Hassel]

Howdy!

The answer of Suresh (and the thread subject title) is wrong.
You are not overriding anything, you are overloading.

Test3 has got four seperate (but overloaded, and three of them inherited) m1-methods:
void m1(A a){...} inherited
void m1(B b){...} inherited
void m1(C c){...} inherited
void m1(Test3 d){...} own

Therefore also your notion that a1 IS_NOT-A Test3 is correct but irrelevant in this context.

Which method will be choosen?
Always the most specific one. Check the FAQ page for "most specific method".

Yours,
Bu.

[suresh mulagala]

sorry overlooked !

[srinivas sridaragaddi]

Thanks Bu for your reply, due to lack of resources i post my doubts at a time, so their was a confusion between overloading and overiding.