Example: Remove Duplicates from Array using HashSet in Java

// Remove Duplicates from Array using HashSet
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.ArrayList;
import java.util.List;

// Main class containing the entry point of the program
public class Main {
    public static void main(String[] args) {
        // Step 1: Define the array with duplicate elements
        Integer[] originalArray = {10, 20, 10, 30, 40, 20, 50, 10};
        System.out.println("Original Array: " + Arrays.toString(originalArray));

        // Step 2: Create a HashSet to store unique elements
        // HashSet automatically handles duplicates
        Set<Integer> uniqueElements = new HashSet<>();

        // Step 3: Iterate through the original array and add elements to the HashSet
        // Adding an element that already exists in a HashSet has no effect.
        for (Integer element : originalArray) {
            uniqueElements.add(element);
        }

        // Step 4: Convert the HashSet back to an array or List if needed
        // Option A: Convert to an ArrayList
        List<Integer> listWithoutDuplicates = new ArrayList<>(uniqueElements);
        System.out.println("List without Duplicates (using HashSet): " + listWithoutDuplicates);

        // Option B: Convert back to an array (if the original array type is needed)
        // You need to specify the size of the new array to the toArray() method.
        Integer[] arrayWithoutDuplicates = uniqueElements.toArray(new Integer[0]);
        System.out.println("Array without Duplicates (using HashSet): " + Arrays.toString(arrayWithoutDuplicates));
    }
}