Java check not null on double

Dear all,

I'm getting a null pointer exception in the following code block.  I've read I can't check for null if its a double. How do I resolve this?

int sumHotWater = CalculateSumHotWater(hotwater_map);
double hotwater = 0;
if (sumHotWater != 0) {
    hotwater = (applianceTotal.get("Hotwater").doubleValue()); // null pointer exception here
    if (hotwater != 0.0) {
        hotwater /= sumHotWater;
    }
}

Select allOpen in new window

Thanks