overloaded-overriden

[Vishnu Prakash]

  class A {void m1(A a) {System.out.print("A");}}
class B extends A {void m1(B b) {System.out.print("B");}}
class C extends B {void m1(C c) {System.out.print("C");}}
class D {
  public static void main(String[] args) {
    A c1 = new C(); B c2 = new C(); C c3 = new C(); C c4 = new C();
    c4.m1(c1); c4.m1(c2); c4.m1(c3);
}}

O/P : ABC

Class B extends class A and Class C extends class B, therefore method m1() is overdidden right?.
But according to the output, method m1() is overloaded. Some one please explain how method m1() is overloaded and not overridden.

[Rajasekar Elango]

Hi,

Here the method m1() in subclasses B and C overloads the method m1() inherited from its parent class A.

Overridding methods should have same method signature, both method parameters and return type should be same.

Thanks,
Raja

[Krishna Srinivasan]

method parameters are different.so it is method overloading.Overridden method signature must be same.

Note:
In Java 1.5 the return type of the overriding method can be different.
When you override a method, the declared return type can be any subclass of the the class returned by the original method. Currently, the method signature of an overriding method has to match exactly that of the method that it is overriding, including the return type.

http://forum.java.sun.com/thread.jspa?threadID=477074&messageID=2215964