Finding the union of two arrays.

Here’s an example of a Java program that finds the union of two arrays:

   import java.util.HashSet;

    public class ArrayUnion {

    public static void main(String[] args) {

        int[] array1 = {1, 2, 3, 4, 5};

        int[] array2 = {4, 5, 6, 7, 8};

       int[] union = findUnion(array1, array2);

        System.out.print("Union of the arrays: ");

        for (int num : union) {

            System.out.print(num + " ");

        }
    }

    public static int[] findUnion(int[] array1, int[] array2) {

        // Create a HashSet to store unique elements from both arrays

        HashSet<Integer> unionSet = new HashSet<>();

        // Add elements from the first array

        for (int num : array1) {

            unionSet.add(num);

        }

        // Add elements from the second array

        for (int num : array2) {

            unionSet.add(num);

        }

        // Convert the unionSet back to an array

        int[] unionArray = new int[unionSet.size()];

        int index = 0;

        for (int num : unionSet) {

            unionArray[index++] = num;

        }    

        return unionArray;

    }

}

In this program, we have a `findUnion` method that takes two arrays as input parameters. It uses a `HashSet` to store unique elements from both arrays. It iterates over each element in both arrays and adds them to the `HashSet`. Finally, it converts the `HashSet` back to an array and returns the resulting union.

In the `main` method, we define two example arrays (`array1` and `array2`). We call the `findUnion` method with these arrays and store the result in the `union` array. Then, we simply print the elements of the `union` array to display the union of the two input arrays.