For primitive array types, you would have to write a reverse sort algorithm:
Alternatively, you can convert your int[] to Integer[] and write a comparator:
public class IntegerComparator implements Comparator<Integer> {
@Override
public int compare(Integer o1, Integer o2) {
return o2.compareTo(o1);
}
}
or use Collections.reverseOrder() since it only works on non-primitive array types.
and finally,
Integer[] a2 = convertPrimitiveArrayToBoxableTypeArray(a1);
Arrays.sort(a2, new IntegerComparator()); // OR
// Arrays.sort(a2, Collections.reverseOrder());
//Unbox the array to primitive type
a1 = convertBoxableTypeArrayToPrimitiveTypeArray(a2);