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Wrong Answer in Master Exam? [equals() and hashCode() Contract]

 
Greenhorn
Posts: 25
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There is a question in Master Exam A mock test:



For me the only correct answer is C, and MasterExam claims that correct answers are C and D. For me answer D is wrong, cause we can imagine the situation where we have two SortOf objects with the following instance variables values:

A:
length=2;
bal=3;
rate=4;

B:
length=2;
bal=4;
rate=3;

Given the equals method from D answer both object are considered equal, cause 2*3*4=2*4*3, but theirs hashCode differs cause 2*3 != 2*4, so the contract is not fulfilled. Is it rather obvious mistake in MasterExam or somehow i get it wrong?
 
Ranch Hand
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I think C is the only correct answer!
For D to be correct the 'rate' has to be declared as a final variable


 
Mana Lesar
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Exactly.
 
Consider Paul's rocket mass heater.
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