Find minimum in a sorted rotated array in O(log n) time

FindMinComparing.java

class FindMinComparing {

        public int findMin(int[] arr) {
            if(arr == null) {
                throw new IllegalArgumentException("Received null array");
            }
            if(arr.length < 1) {
                throw new IllegalArgumentException("Received zero-length array");
            }
            if(arr.length == 1) {
                return arr[0];
            }
            return findMin(arr, 0, arr.length - 1);
        }

        int findMin(int[] arr, int lo, int hi) {
            int mid = lo + ( (hi - lo) / 2);
            if(mid > 0 && arr[mid] < arr[mid - 1]) {
                return arr[mid];
            } else if(arr[mid] > arr[hi]) {
                return findMin(arr, mid + 1, hi);
            } else {
                return findMin(arr, lo, mid - 1);
            }
        }
    }