Here is a Java program to convert an array to a HashSet and a HashSet to an array:

import java.util.Arrays;
import java.util.HashSet;

public class ConvertArrayToSetAndSetToArray {
    public static void main(String[] args) {
        
        // Convert array to HashSet
        String[] arr = {"apple", "banana", "orange", "apple"};
        HashSet<String> set = new HashSet<>(Arrays.asList(arr));
        System.out.println("HashSet: " + set);
        
        // Convert HashSet to array
        String[] newArr = set.toArray(new String[set.size()]);
        System.out.println("Array: " + Arrays.toString(newArr));
    }
}

This program first creates an array of strings, arr. It then converts the array to a HashSet using the Arrays.asList() method to create a List from the array, and passing the List to the HashSet constructor. The HashSet constructor removes any duplicate elements in the array, so the resulting HashSet contains only unique elements.

Next, the program converts the HashSet back to an array using the toArray() method of the HashSet class. The resulting array has the same elements as the original array, but the order may be different because a HashSet does not guarantee element order.

Note that this program assumes that the array and the HashSet contain only elements of the same type (in this case, String). If the array or HashSet contains elements of different types, then you will need to use a generic type (e.g., Object) and perform type casting.