Add elements to a collection

boolean add(E e)

Ensures that this collection contains the specified element (optional operation).

boolean addAll(Collection<? extends E> c)

Adds all of the elements in the specified collection to this collection (optional operation).

import java.util.ArrayList;
import java.util.Collection;

public class Main {

  public static void main(String args[]) {
     Collection collection = new ArrayList();
     collection.add("java2s.com");
     
     System.out.println(collection);
  }
}

The output:

[java2s.com]

1. Collection interface
2. Add elements to a collection
3. Is it contained in the collection
4. Compare two collections
5. Remove elements from a collection
6. Convert collection to Array
7. Get the size of a Collection
8. Is a collection empty
9. Clear a collection
10. Get the iterator() from a collection