AbstractCollection addAll() Method in Java with Examples

Last Updated : 26 Nov, 2018

The addAll(Collection C) method of Java AbstractCollection is used to append all of the elements from a mentioned collection to this collection. The elements are added randomnly without following any specific order.

Syntax:

boolean addAll(Collection C)

Parameters: The parameter C is a collection of any type that is to be added to the collection.

Return Value: The method returns true if it successfully appends the elements of the collection C to the existing collection otherwise it returns False.

Below programs illustrate the AbstractCollection.addAll() method:

Program 1:

// Java code to illustrate addAll() 
// method of AbstractCollection 
  
import java.util.*; 
import java.util.AbstractCollection; 
  
public class AbstractCollectionDemo { 
    public static void main(String args[]) 
    { 
  
        // Creating an empty collection 
        AbstractCollection<String> 
            abs1 = new TreeSet<String>(); 
  
        // Use add() method to add 
        // elements into the Collection 
        abs1.add("Welcome"); 
        abs1.add("To"); 
        abs1.add("Geeks"); 
        abs1.add("4"); 
        abs1.add("Geeks"); 
        abs1.add("TreeSet"); 
  
        // Displaying the Collection 
        System.out.println("AbstractCollection 1: "
                           + abs1); 
  
        // Creating anothe Collection 
        AbstractCollection<String> 
            abs2 = new TreeSet<String>(); 
  
        // Displaying the Collection 
        System.out.println("AbstractCollection 2: "
                           + abs2); 
  
        // Using addAll() method to Append 
        abs2.addAll(abs1); 
  
        // Displaying the Collection 
        System.out.println("AbstractCollection 2: "
                           + abs2); 
    } 
} 

Output:

AbstractCollection 1: [4, Geeks, To, TreeSet, Welcome]
AbstractCollection 2: []
AbstractCollection 2: [4, Geeks, To, TreeSet, Welcome]

Program 2:

// Java code to illustrate addAll() 
// method of AbstractCollection 
  
import java.util.*; 
import java.util.AbstractCollection; 
  
public class AbstractCollectionDemo { 
    public static void main(String args[]) 
    { 
  
        // Creating an empty collection 
        AbstractCollection<Integer> 
            abs1 = new TreeSet<Integer>(); 
  
        // Use add() method to add 
        // elements into the Collection 
        abs1.add(10); 
        abs1.add(20); 
        abs1.add(30); 
        abs1.add(40); 
        abs1.add(50); 
  
        // Displaying the Collection 
        System.out.println("AbstractCollection 1: "
                           + abs1); 
  
        // Creating anothe Collection 
        AbstractCollection<Integer> 
            abs2 = new TreeSet<Integer>(); 
  
        // Displaying the Collection 
        System.out.println("AbstractCollection 2: "
                           + abs2); 
  
        // Using addAll() method to Append 
        abs2.addAll(abs1); 
  
        // Displaying the Collection 
        System.out.println("AbstractCollection 2: "
                           + abs2); 
    } 
} 

Output:

AbstractCollection 1: [10, 20, 30, 40, 50]
AbstractCollection 2: []
AbstractCollection 2: [10, 20, 30, 40, 50]

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