Java Collections addAll() Method

The addAll() is a method of Java Collections class which adds all of the specified elements to the specified collection. The elements to be added may be specified individually or as an array.

Syntax

Following is the declaration of addAll() method:

Parameter

Parameter	Description	Required/Optional
c	It is a collections into which elements are to be inserted.	Required
elements	Elements are the elements to be inserted into c.	Required

Returns

The addAll() method returns true if the collection changed as a result of the method call.

Exceptions

UnsupportedOperationException- If collection c does not support the add operation.

NullPointerException- If elements contain null values and c does not permit null elements, or if c or elements are null.

IllegalArgumentException- If some properties of a value in elements prevent it from being added to c.

Compatibility Version

Java 1.5 and above

Example 1

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
public class CollectionsAddAllExample1 {
	public static void main(String[] args) {
		Set<Integer> set = new HashSet<>();
            boolean b = Collections.addAll(set, 1, 2, 3, 4, 5);
            System.out.println("Boolean Result: "+b);
            System.out.println("Collection Value: "+set);		
	      }
}

Test it Now

Output:

Boolean Result: true
Collection Value: [1, 2, 3, 4, 5]

Example 2

import java.util.*;
public class CollectionsAddAllExample2 {
	public static void main(String[] args) {
		List<String> alist = new ArrayList<String>();
		alist.add("Rahul");
		alist.add("Karthik");
		alist.add("OM");
		alist.add("Shiva");
		alist.add("Anand");
		alist.add("Prem");
		System.out.println("The List are: "+alist);
		boolean b = Collections.addAll(alist, "Rahul", "OM", "Prem");
		System.out.println("Boolean Result: "+b);
		System.out.println("Collection Value: "+alist);
	    }
}

Test it Now

Output:

The List are: [Rahul, Karthik, OM, Shiva, Anand, Prem]
Boolean Result: true
Collection Value: [Rahul, Karthik, OM, Shiva, Anand, Prem, Rahul, OM, Prem]

Example 3

import java.util.*;
public class CollectionsAddAllExample3 {
	public static void main(String[] args) {
		//Create object of an array list        
	      List<String> alist = new ArrayList<String>();
	      //Add values to the list
	      alist.add("JavaTpoint");
	      alist.add("SSSIT.COM");
	      alist.add("Hindi100.COM");  
	      System.out.println("Initial collection value: "+alist);
	      //Add values to this collection and print Final collection Result
	      boolean b = Collections.addAll(alist, "Rank1","Rank2","Rank3");
	      System.out.println("Boolean Result: "+b);
	      System.out.println("Final collection value: "+alist);
	    }
}

Test it Now

Output:

Initial collection value: [JavaTpoint, SSSIT.COM, Hindi100.COM]
Boolean Result: true
Final collection value: [JavaTpoint, SSSIT.COM, Hindi100.COM, Rank1, Rank2, Rank3]

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