Var-args

[Meena R. Krishnan]

class Base1{
void printStr(String... args){
System.out.println("Base.print");
}
}
class Derived1 extends Base1{
void printStr(){
System.out.println("Derived.print");
}
/*
void printStr(String[] str){
System.out.println("Derived.print(string[])");
}*/
}
public class VarArgsTest {
 
public static void main(String... args){
Base1 b = new Derived1();
b.printStr();  //prints "Base.print".why??
        ((Derived1)b).printStr();  //prints "Derived1.print" which is fine.
}
}

The above code prints "Base.print" while I was expecting the derived class' method to be called. why?

[ May 13, 2007: Message edited by: M Krishnan ]
[ May 14, 2007: Message edited by: M Krishnan ]

[anil kumar]

Hi

M Krishnan


you are overloading the printSrt() method.In the base that method has parameters ,which accepts 0 to n arguments.

And in the derived class,it is not accepting parameters.

If you override that method in the derived class you will get the result you want.

Thanks
Anil Kumar

[Meena R. Krishnan]

And in the derived class,it is not accepting parameters.

Yes that's correct, since I am calling a method with no arguments I would expect the derived class' method to be called.

[Keith Lynn]

Originally posted by M Krishnan:

class Base1{
void printStr(String... args){
System.out.println("Base.print");
}
}
class Derived1 extends Base1{
void printStr(){
System.out.println("Derived.print");
}
/*
void printStr(String[] str){
System.out.println("Derived.print(string[])");
}*/
}
public class VarArgsTest {
 
public static void main(String... args){
Base1 b = new Derived1();
b.printStr();  //prints "Base.print".why??
        ((Derived1)b).printStr();  //prints "Derived1.print" which is fine.
}
}

The above code prints "Base.print" while I was expecting the derived class' method to be called. why?

[ May 13, 2007: Message edited by: M Krishnan ]

[ May 14, 2007: Message edited by: M Krishnan ]

The thing to notice here is that you are calling the method printStr using a Base1 reference.

That means that even though the object is of runtime type Derived1, you can only call methods on the Base1 reference that are visible to the Base1 class.

In this case that means that the only method you can call on the reference is the method printStr defined in Base1 and inherited by Derived1.