How can we find the intersection of multiple arrays in Java?

You can use HashSet to find the intersection of multiple arrays. The specific steps are as follows:

1. Convert the first array into a HashSet.
2. Traverse through the other arrays and add their elements to the HashSet of the first array.
3. In the end, the HashSet is simply the intersection of all the arrays.

Here is a sample code:

import java.util.*;

public class ArrayIntersection {
    public static void main(String[] args) {
        int[] arr1 = {1, 2, 3, 4, 5};
        int[] arr2 = {3, 4, 5, 6, 7};
        int[] arr3 = {5, 6, 7, 8, 9};
        
        Set<Integer> set = new HashSet<>();
        for (int num : arr1) {
            set.add(num);
        }
        
        for (int i = 1; i < 3; i++) {
            Set<Integer> tempSet = new HashSet<>();
            for (int num : set) {
                if (contains(arr2, num) && contains(arr3, num)) {
                    tempSet.add(num);
                }
            }
            set = tempSet;
        }
        
        System.out.println("Intersection of arrays: " + set);
    }
    
    public static boolean contains(int[] arr, int num) {
        for (int i : arr) {
            if (i == num) {
                return true;
            }
        }
        return false;
    }
}

Please note that the code uses a contains method to determine if an element is present in an array, making it easy to check if the element is present in all arrays.