method not working outside of class

**Scotty** · April 22nd, 2011, 01:38 PM

I have a 2D-array in a class, and methods that affect the array.

From another class I can call a method to add to the array which works fine.

My method to get a value from an array is:

 
public int getValue(int col, int row){
 
		return myArray[col][row];
	}

I can call it in that class and it works fine (returns correct int), but from another class I always get a null pointer exception. All other methods work from another class (ie to set a value in the array). Why cant I return the value?

int Number = class.getValue(); -- null pointer.

**KevinWorkman** · April 22nd, 2011, 01:53 PM

Sounds like your reference to "class" is null. Are you sure you're initializing it?

That's just a guess though. If you want more help, you'll have to provide an SSCCE that demonstrates the problem. That doesn't mean you should post your whole program- just the bare essentials.

**Scotty** · April 22nd, 2011, 02:53 PM

I can use other methods, for example

state.setArray(2);

Which puts a value in row 2 and then prints the array. These work fine.
It is definitely initialised. I cannot post code.

I have tried

public int getValue(int col, int row) {
int Number = myArray[col][row];
return Number;
}

state state;
state.getValue(1,2);
 
also
 
state teststate = new state();
teststate.getvaule(1,2);
 
for a copy of state

But I get the same error. I dont see why that would work if the other one didnt.

**KevinWorkman** · April 23rd, 2011, 10:00 AM

If you can't post an SSCCE, then we can't really help you. Are you sure the array is initialized?

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