In this program, You will learn how to find union and intersection of two arrays in java.

```
The first list is: 1 2 3 4 5
The second list is: 3 4 5
Union is: 1 2 3 4 5
Intersection is: 3 4 5
```

## Example: How to find union and intersection of two arrays in java.

```
import java.util.Scanner;
class Main {
void printUnion(int arr1[], int arr2[], int len1, int len2) {
int f, i, j, k = 0;
int arr3[] = new int[100];
for (i = 0; i < len1; i++) {
arr3[k] = arr1[i];
k++;
}
for (i = 0; i < len2; i++) {
f = 0;
for (j = 0; j < len1; j++) {
if (arr2[i] == arr1[j]) {
f = 1;
}
}
if (f == 0) {
arr3[k] = arr2[i];
k++;
}
}
System.out.print("\nUnion of Two Array is :");
for (i = 0; i < k; i++) {
System.out.print(" " + arr3[i]);
}
}
void printIntersection(int arr1[], int arr2[], int len1, int len2) {
int arr3[] = new int[100];
int i, j, k = 0;
for (i = 0; i < len1; i++) {
for (j = 0; j < len2; j++) {
if (arr1[i] == arr2[j]) {
arr3[k] = arr1[i];
k++;
}
}
}
System.out.print("\nIntersection of Two Array is :");
for (i = 0; i < k; i++) {
System.out.print(" " + arr3[i]);
}
}
public static void main(String args[]) {
int arr1[] = new int[100];
int arr2[] = new int[100];
int i, j, len1, len2;
Scanner sc = new Scanner(System.in);
System.out.print("Enter Size of 1st Array :");
len1 = sc.nextInt();
System.out.print("Enter 1st Array Elements :");
for (i = 0; i < len1; i++) {
arr1[i] = sc.nextInt();
}
System.out.print("Enter Size of 2nd Array :");
len2 = sc.nextInt();
System.out.print("Enter 2nd Array Elements :");
for (i = 0; i < len2; i++) {
arr2[i] = sc.nextInt();
}
Main tt = new Main();
tt.printUnion(arr1, arr2, len1, len2);
tt.printIntersection(arr1, arr2, len1, len2);
}
}
```

#### Output:

```
Enter Size of 1st Array :5
Enter 1st Array Elements :10 20 30 40 50
Enter Size of 2nd Array :4
Enter 2nd Array Elements :30 40 50 60
Union of Two Array is : 10 20 30 40 50 60
Intersection of Two Array is : 30 40 50
```