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q from a mock exam

 
Greenhorn
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Read the following code and can anybody explain how the code works
class Dumb{
Dumb(){
Object y = new X();
((X)y).m(y);
String in1 = y.toString();
}
public static void main(String[] args){
new Dumb();
}
}
class X {
public void m (Object x)
{
System.out.println("In m "+x);
}
public String toString()
{
System.out.println("ToSTring in Tostring");
return "123";
}
}
 
Rancher
Posts: 1449
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Hi,
This doesn't answer your question but the best way for you to learn what this does is code it up and throw some println's in to track where you are.
John
 
Ranch Hand
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Output:
ToSTring in Tostring
In m 123
ToSTring in Tostring
Reason:
operator+ is overriden to handle strings. i.e. if one of the operands is a string & the other a Object, then its
toString() method is called. Since we have overridden the toString method of Object class for class X,
this is invoked implicitly in the println() statement.
-Aj

[This message has been edited by Aj Patel (edited January 07, 2001).]
 
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