pass all the requirement without output It's should like: Apple 22 Bob 3 Cherry 1 0 Watermelon But just red color Exception, like NullPointer..... below it's my sort code, can some one find any problem? (I think it's in number sorting, but I can not locate it) Appreciate your help !!! ===================================================== public static void sort(String[] array) { // write your code here // sorting numbers in descending order. String temp; for (int i = 0; i < array.length-2; i++) { if(!isNumber(array[i])) continue; for (int j = i+1; j < array.length-1; j++) { if(!isNumber(array[j])) continue; // if( array[i] < array[j]) if (Integer.parseInt(array[i])<Integer.parseInt(array[j])){ temp = array[j]; array[j] = array[i]; array[i] = temp; } } } // sorting Stings in ascending order for (int k = 0; k < array.length-1; k++) { if(isNumber(array[k])) continue; for (int m = k + 1; m < array.length; m++) { if(isNumber(array[m])) continue; if(isGreaterThan(array[k] , array[m])) { temp = array[m]; array[m] = array[k]; array[k] = temp; } } } }