Find an Intersection between two integer arrays

IntersectionSearch.java

/*
 * Example Arr1 = {2,3,7,9,20,35} ; Arr2 = { 3,9,21,35,89,100,200}, Intersection = {3,9,35}
 * Assumptions:
 * Both Arrays are sorted
 * Both Arrays contain at least one element
 * Arr2 >> Arr1 
 * n is Arr1.length, m is Arr2.length
 * Possible Solutions:
 * (1) Brute-force : run O(nm) - inefficient
 * (2)HashSet/Map : O(n+m) runtime, O(k) additional space k = size of hashset/map
 * (3)Merge subroutine of merge sort : O(n+m) run, O(k) additional array space
 * Better solution(4)linear search Arr1, binary search Arr2: O(nlogm) since m >> n and logm >> logn
*/
public class IntersectionSearch {

    public static List<Integer> findIntersection(int [] arr1, int [] arr2){
        List<Integer> intersection = new ArrayList<>();

        for(int i = 0; i < arr1.length; i++){
            int item = arr1[i];

            if(binarySearch(arr2, item)) intersection.add(item);
        }


        return intersection;
    }

    public static boolean binarySearch(int [] arr2, int key){

        int begin = 0;
        int end = arr2.length-1;

        while(begin <= end){
            int mid = begin + ((end - begin)/2);

            if(key == arr2[mid]) return true;

            if(key > arr2[mid]) begin = mid + 1;

            if(key < arr2[mid]) end = mid - 1;

        }

      return false;
    }
   //test harness
    public static void main(String [] args){

        int [] arr1 = {2, 3,35,89,150};

        int [] arr2 = {3, 9, 21, 35, 89, 100,150, 200};

        List<Integer> inter = findIntersection(arr1, arr2);

        for(Integer i : inter){
            System.out.print(i + ",");
        }

    }
}