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method overridding  RSS feed

 
Pramod P Deore
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Android Eclipse IDE Java
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what will be the output of the followinf code? Please explain it in brief



which of the following methods inserted independently at the indicated line in the following code can cause it to compile correctly?

class SuperBase { }
class Base extends SuperBase { }
class Derived extends Base { }

class CovariantTest1
{
public Base getIt()
{
return new Base();
}
}

class SubCovariantTest extends CovariantTest1
{
// insert code here

}

select any 2 options:
[a] public Derived getIt() { return new Derived(); }
[b] public Base getIt() { return new Derived(); }
[c] public SuperBase getIt() { return new Derived(); }
[d] public SuperBase getIt() { return new Base(); }
[e] public Derived getIt() { return new Base(); }
 
jean-gobert de coster
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It would be A and B

as of java 5 you may override a method by returning a subclass of it's overriden return type, so A is correct.

B is correct because you can a Derived IS-A Base

C and D are incorrect because the new return type is not a subclass of Base

E is incorrect because you would need an explicit cast from Base to Derived
 
Pawan Arora
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Option A and B are the correct answer.
 
Ankit Garg
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pramod please quote your source...
 
James Tharakan
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Its from Whiz Lab trail version
 
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