null pointer exception

Question

the value memanufacturer is retrieved from xml document using jdom and when this value is assigned to meman array it throws NullPointerException.

Element memanufacturer = (Element) row27.get(j9);
        meman[0] = memanufacturer.getValue();

what could be the posssible mistake.

Thanks

Answer 1

Assuming the exception by the second line of code, there are two obvious possibilities:

• memanufacturer may be null
• meman may be null

We can't tell which of these is the case, but you should be able to.

EDIT: Okay, so now we know that meman is null, that's the problem. I would suggest you use a List<String> instead:

List<String> meman = new ArrayList<String>();

...
Element memanufacturer = (Element) row27.get(j9);
meman.add(memanufacturer.getValue());

Using a List<String> instead of an array means you don't need to know the size before you start.

However, the fact that you didn't understand the error suggests you should really read a good introductory Java book before going any further with a real project. You should definitely understand how arrays, collections etc work before dealing with XML and the like. It will save you a lot of time in the long run.