Where do you set the value of loopCount? What the upper bound for it? what's the upperbound of orderArray? How many rows do you have in resultsGrid? Those are the questions you should ask yourself whenever you run into "index out of range" exception. And keep in mind that collections/arrays are zero based index, so for example, if you have an array with 50 elements, the index goes from 0 to 49 instead of 1 to 50.