public static void main(String args[]){
        FindNumberOccurringOnceOtherNumbers3Times fno = new FindNumberOccurringOnceOtherNumbers3Times();
        int arr[] = {1,1,2,5,6,1,6,6,2,2};
//      int arr[] = {1,1,1,4,1,1,1};
        System.out.println(fno.getNumberOccurringOnce(arr));
    }
http://www.geeksforgeeks.org/find-the-element-that-appears-once/
src/com/interview/bits/FindNumberOccurringOnceOtherNumbers3Times.java