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Need explaination

Rajesh k Jha
Ranch Hand

Joined: May 10, 2009
Posts: 72
This question is from ExamLab6.0 Mock test.
Here i m confused with the answer that is given, answer says that A and B is the right answer, but i m not sure how B is the correct answer, can
somebody explain the concept behind this?

A) A[1]=new A();
B) a[0]=new B();
C) a[0]=new C();
D) a[0]=new D();
E) a[0]=new Object();
F) Existing code gives a compile time error.
G) Existing code gives a runtime exception.
Ankit Garg

Joined: Aug 03, 2008
Posts: 9313

What does the question says about the options?? Does it says that which of these will compile fine or which will compile and run fine or something else??

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Nitish Bangera
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Joined: Jul 15, 2009
Posts: 537

A will give a Array indexoutofbound exception And B will give an Arraystoreexception because the array object is supposed to store c and its subclass objects and B is not a subclass of C. I suppose this question only asks for exceptions. If its not then E will give a compile time error. Because Object is not a A. A is-a Object. For compilation this relationship should be passed with the reference variable type.

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Rajesh k Jha
Ranch Hand

Joined: May 10, 2009
Posts: 72
Hello Ankit, actually this question is asking "Which inserted independently at the commented line, will produce an exception at the runtime?
choose two answer
Rajesh k Jha
Ranch Hand

Joined: May 10, 2009
Posts: 72
Thanks Nitish, your explanation is really superb, it really helped me understand the whole concept hidden behind this programme, excellent job man
Don't get me started about those stupid light bulbs.
subject: Need explaination