Handling null objects in an array

Question

I have an array with 18 objects in it, and the array is allocated to have 25 objects in it (the remaining 7 objects are null for future use). I’m writing a program that prints out all the non-null objects, but I’m running in to a NullPointerException and I can’t figure out how to get around it.

When I try this, the program crashes with Exception in thread "main" java.lang.NullPointerException:

        for(int x = 0; x < inArray.length; x++)
        {
            if(inArray[x].getFirstName() != null)//Here we make sure a specific value is not null
            {
                writer.write(inArray[x].toString());
                writer.newLine();
            }
        }

And when I try this, the program runs, but still prints the nulls:

        for(int x = 0; x < inArray.length; x++)
        {
            if(inArray[x] != null)//Here we make sure the whole object is not null
            {
                writer.write(inArray[x].toString());
                writer.newLine();
            }
        }

Can anyone point me in the right direction for handling null objects in an array? All help is appreciated!

I am surprised that the second version doesn't work. Are you sure it still prints the nulls? — Louis Wasserman
– Louis Wasserman, Commented May 8, 2012 at 17:47
I think Louis is correct. There is not any problem with the second version of code. — Bhavik Ambani
– Bhavik Ambani, Commented May 8, 2012 at 17:48
"but still prints the nulls", are you sure? Have you overrided the method toString() in your class? — user800014
– user800014, Commented May 8, 2012 at 17:49
@LouisWasserman Maybe: inArray[x] != null but inArray[x].toString() prints null. — assylias
– assylias, Commented May 8, 2012 at 17:50

Habib · Accepted Answer · 2012-05-08 17:49:08Z

9

your check should be:

if(inArray[x] != null && inArray[x].getFirstName() != null)

answered May 8, 2012 at 17:49

Habib

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1 Comment

Andrew De Forest Over a year ago

Thank you @Habib.OSU, I will accept this when I can. So simple, not sure why I didn't try it!

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