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Java program to add a HashSet to another HashSet collection

Java example to add a HashSet to another HashSet collection.
Submitted by Nidhi, on May 09, 2022

Problem Solution:

In this program, we will create two sets using the HashSet collection to store integer elements. Then we will add a HashSet into another HashSet using the addAll() method.

Program/Source Code:

The source code to add a HashSet to another HashSet collection is given below. The given program is compiled and executed successfully.

// Java program to add a HashSet to another 
// HashSet collection

import java.util.*;

public class Main {
  public static void main(String[] args) {
    HashSet < Integer > nums = new HashSet();
    HashSet < Integer > nums1 = new HashSet();

    nums.add(1);
    nums.add(2);
    nums.add(3);
    nums.add(4);

    nums1.add(10);
    nums1.add(20);
    nums1.add(30);
    nums1.add(40);

    System.out.println("Set1: " + nums);
    System.out.println("Set2: " + nums1);

    nums.addAll(nums1);

    System.out.println("\nSet1: " + nums);
    System.out.println("Set2: " + nums1);
  }
}

Output:

Set1: [1, 2, 3, 4]
Set2: [20, 40, 10, 30]

Set1: [1, 2, 3, 4, 20, 40, 10, 30]
Set2: [20, 40, 10, 30]

Explanation:

In the above program, we imported the "java.util.*" package to use the HashSet collection. Here, we created a public class Main that contains a main() method.

The main() method is the entry point for the program. And, we created two sets nums, and nums1 to store integer data elements using HashSet collection. Then we added nums HashSet into nums1 HashSet using addAll() method. After that, we printed updated sets.

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