Languages
[Edit]
EN

Java - add ArrayList into HashSet

0 points
Created by:
Dirask Community
6360

In this article, we would like to show you how to add ArrayList into HashSet in Java.

 

1. Add ArrayList on HashSet creation

In this example, we add existing letters ArrayList to a new alphabet HashSet in the constructor.

import java.util.*;

public class Example {

    public static void main(String[] args) {
        List<String> letters = new ArrayList<>();

        letters.add("A");
        letters.add("B");
        letters.add("C");

        Set<String> alphabet = new HashSet<>(letters);

        System.out.println(alphabet);
    }
}

Output:

[A, B, C]

2. Add ArrayList to the existing HashSet

In this example, we add existing letters ArrayList to the existing alphabet HashSet using addAll() method.

import java.util.*;

public class Example {

    public static void main(String[] args) {
        Set<String> alphabet = new HashSet<>();
        
        alphabet.add("A");
        alphabet.add("B");
        alphabet.add("C");

        List<String> letters = new ArrayList<>();

        letters.add("D");
        letters.add("E");
        letters.add("F");

        alphabet.addAll(letters);

        System.out.println(alphabet);
    }
}

Output:

[A, B, C, D, E, F]
Native Advertising
🚀
Get your tech brand or product in front of software developers.
For more information Contact us
Dirask - we help you to
solve coding problems.
Ask question.

❤️💻 🙂

Join