Derefrencing of 'binding' produces NullPointer Exception

Declare an array of Croller(https://android-arsenal.com/details/1/5079) -

Croller[] croller = new Croller[]{binding.crollerThirtyOnetwentyHertz,binding.crollerOnetwentyFoursixtyHertz,binding.crollerFoursixtyOnekiloHertz,
                        binding.crollerOnekiloSevenkiloHertz,binding.crollerSevenkiloHertz};

Use it: On setting the label of Croller using data binding shows Null Pointer Exception

for (int i = 0; i < numBands; i++)
{
    freqRange = eq.getBandFreqRange((short)i);
    croller[i].setLabel ("Anything Printed Here"));
}