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Nullpointer Exception problem

 
Greenhorn
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in the following program I get a Nullpointer exception at line 96.the program reads a large list of values from a file and puts them into an array.the file does not contain any null values.pl,ease help me with this code
 
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Can you point out the line where the exception is coming. Line number 96 in your code is empty...
 
shanaya dutt
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line 97...it may occur at 100 too
 
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mparr is null, because you never give it any value.

And with "it" I don't mean mparr itself but mpplot's array field.
 
shanaya dutt
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i did the following modification but it still throws an exception.Now at mparr assignment part at line 88.where am i going wrong?

 
Rob Spoor
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You still never assign the array field. You create two double arrays, sure, but those are method local variables.
 
shanaya dutt
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okay!!
But then whats wrong with this code.Here i'm directly accessing the array from the mpplot class.it still throws the exception at the comparison in paint.

 
Rob Spoor
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shanaya dutt wrote:


Where do you give it a value? The answer: nowhere. Therefore, it will remain null.
 
Consider Paul's rocket mass heater.
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