Take studentercord out from settee Anna is the object and you call set on that
e.g
anna.setName("Anna");
Nick
07961171046
-----Original Message-----
From: Mihai DINCA <[email protected]>
Date: Sat, 15 May 2010 11:05:35
To: <[email protected]>
Cc: Java Programming Online Training Course By Sang
Shin<[email protected]>
Subject: Re: [java programming] Re: Homework 1014
I think your constructor for the class Student must do "studentRecord =
new StrudentRecord()" or something like this.
Hope it helps
mihai
JKay a écrit :
> Tried to post the entire project here, but moderator said no.
> Apparently we're not allowed to post large volumes of code, just small
> snippets?
>
> The project is 3 classes (StudentRecordExample.java[MAIN],
> StudentRecord.java,Student.java), which have been modified from the
> original MyStudentRecordExampleProject so its a bit bulky and could do
> with a lot of streamlining, but I figure it should work anyways. As
> said the error I'm getting is:
>
> Exception in thread "main" java.lang.NullPointerException
> at StudentRecordExample.main(StudentRecordExample.java:35)
> Java Result: 1
>
> I used the 'new' keyword to create an instance of a Student object
> like so in StudentRecordExample.java:
>
> Student anna = new Student();
>
> Then to set the name variable for object anna of class Student, I
> used:
>
> anna.studentRecord.setName("Anna");
>
> which as I understand it gets method setName from class studentRecord.
> Do I have to explicitly link classes Student and StudentRecord some
> how for this to work? BTW this line of code where I set anna's name
> variable is highlighted when I click on the error, and is on line 35.
>
> On May 14, 6:00 pm, Nic Fox <[email protected]> wrote:
>
>> Without seeing your code it's hard to say.
>>
>> So you've used the 'new' keyword to make an instance of a Student
>> object?
>> E.g. Student anna = new Student();
>>
>> And then you use something like:
>> anna.name = "Anna";
>>
>> If you've done those things then it could be an issue with variable
>> scope perhaps?
>>
>> On 14/05/2010, at 11:47 PM, JKay wrote:
>>
>>
>>
>>
>>> I keep getting the following error when I run my program:
>>>
>>> Exception in thread "main" java.lang.NullPointerException
>>> at StudentRecordExample.main(StudentRecordExample.java:35)
>>>
>>> I looked up what java.lang.NullPointException is in the API and found
>>> this:
>>>
>>> "public class NullPointerException
>>> extends RuntimeException
>>>
>>> Thrown when an application attempts to use null in a case where an
>>> object is required. These include:
>>>
>>> * Calling the instance method of a null object.
>>> * Accessing or modifying the field of a null object.
>>> * Taking the length of null as if it were an array.
>>> * Accessing or modifying the slots of null as if it were an array.
>>> * Throwing null as if it were a Throwable value.
>>>
>>> Applications should throw instances of this class to indicate other
>>> illegal uses of the null object."
>>>
>>> Which as far as I understand means that I'm trying to do something
>>> with a null object. Said object is object anna of class Student, and
>>> the method on the line that is throwing the exception is me attempting
>>> to set the name variable for anna to "Anna"
>>>
>>> Any ideas?
>>>
>>> James
>>>
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>
>
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