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Comparator

 
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Hi...

I'm getting the error :"int cannot be dereferenced" for the following code:



What is the problem??
 
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i think a.getFirst() method is returning int.
using int you can't call a method ...
you are doing something like 5.compareTo()
 
Duran Harris
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Nope...

getFirst() returns a String..first name
 
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Just use a cast if a.getFirst actually returns an int

((Integer)a.getFirst()).compareTo(b.getFirst())
 
Duran Harris
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Look:

 
James Tharakan
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we have given the solution , now go through the code again
 
Ankit Garg
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I think this code will give the error

46. return (a.getAge()).compareTo(b.getAge());

and not this one

56. return (a.getFirst()).compareTo(b.getFirst());
 
Duran Harris
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Hmm doesn't int implement Comparable?
 
Duran Harris
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Maybe I should change to Integer
 
Ankit Garg
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Duran Harris wrote:Hmm doesn't int implement Comparable?



int is a primitive datatype. It cannot implement anything
 
James Tharakan
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Ankit Garg wrote:Just use a cast if a.getFirst actually returns an int

((Integer)a.getFirst()).compareTo(b.getFirst())



this is better option
 
Duran Harris
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Ok that's fixed...

but now I have a null pointer exception in populateArray() ops:
 
Ankit Garg
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Did you call createCustomer before calling populateArray??
 
Duran Harris
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yes,and I can see the customers.txt file that has been created...
 
James Tharakan
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Nothing
 
Duran Harris
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well I changed the customer[] to an arraylist and it works..
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