Find common elements out of two sorted array

FindCommonElementsInTwoArrays.java

import java.util.ArrayList;

public class FindCommonElementsInTwoArrays {

    public ArrayList<Integer> findCommonElementsOfTwoArray(int[] array1, int[] array2) {

        int[] larger = array1;
        int[] smaller = array2;

        if (array1.length < array2.length) {

            larger = array2;
            smaller = array1;
        }

        ArrayList<Integer> commonElementList = new ArrayList<>();
        for (int i = 0; i < smaller.length; i++) {

            int x = bs(larger, 0, larger.length - 1, smaller[i]);
            if (x == smaller[i]) {

                commonElementList.add(x);
            }
        }

        return commonElementList;
    }

    private int bs(int[] numbers, int left, int right, int key) {

        if (left <= right) {

            int mid = (left + right) / 2;

            if (key == numbers[mid]) {

                return key;
            }

            if (key > numbers[mid]) {

                return bs(numbers, mid + 1, right, key);
            } else {

                return bs(numbers, 0, mid - 1, key);
            }
        }

        return -1;
    }
}

FindCommonElementsInTwoArraysTest.java

import static org.junit.Assert.assertEquals;

import java.util.ArrayList;

import org.junit.Before;
import org.junit.Test;

public class FindCommonElementsInTwoArraysTest {

    private FindCommonElementsInTwoArrays testClass;

    @Before
    public void setUp() {

        testClass = new FindCommonElementsInTwoArrays();
    }

    @Test
    public void findCommonElemsEx1() {

        int[] array1 = { 2, 5, 8, 17, 18, 34, 37, 55 };
        int[] array2 = { 3, 4, 5, 18, 31, 32, 55 };

        ArrayList<Integer> commonList = testClass.findCommonElementsOfTwoArray(array1, array2);

        assertEquals(5, commonList.get(0).intValue());
        assertEquals(18, commonList.get(1).intValue());
    }
}

We can do this in O(m) as here we assumed both arrays are sorted. The above Algorithm will give O(mlogn) complexity.
Here m - the size of smaller array and n - the size of a bigger array.

Following code will give O(m) time complexity and O(1) space complexity.

public static ArrayList<Integer> getCommonElements(int[] arr1, int[] arr2) {
		int m = arr1.length;
		int n = arr2.length;
		ArrayList<Integer> result = new ArrayList<Integer>();
		int i = 0; int j = 0;
		while (i < m && j < n) {
			if (arr1[i] < arr2[j]) {
				i++;
			} else if (arr1[i] > arr2[j]) {
				j++;
			} else {
				//both are equals
				result.add(arr1[i]);
				i++;
				j++;
			}
		}
		return result;
	}