lastIndexOf

   /**
     * Finds the index of the last occurrence of <code>target</code> in <code>source</code>
     * @param source the array that we are checking.
     * @param target the element which index we are looking for
     * @return integer index of target
     *
     * @author Dimitar Naydenov
     */
    public static int lastIndexOf(int[] source, int target) {
        if (source.length == 0){
            return -1;
        }
        for (int i = source.length-1; i >= 0 ; i--) {
            if (source[i] == target){
                return i;
            }
        }
        return -1;
    }