Java ArrayList addAll() Method

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Description

The Java ArrayList addAll(Collection<? extends E> c) method appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's Iterator. The behavior of this operation is undefined if the specified collection is modified while the operation is in progress(implies that the behavior of this call is undefined if the specified collection is this list, and this list is nonempty).

Declaration

Following is the declaration for java.util.ArrayList.addall(c) method

public boolean addAll(Collection<? extends E> c)

Parameters

c − This is the collection containing elements to be added to this list.

Return Value

This method returns true if this list changed as a result of the call.

Exception

NullPointerException − If the specified collection is null

Java ArrayList addAll(index, collection) Method

Declaration

Following is the declaration for java.util.ArrayList.addall(index, c) method

public boolean addAll(int index, Collection<? extends E> c)

Parameters

• index − The index at which to insert the first element from the specified collection.

• c − This is the collection containing elements to be added to this list.

Return Value

This method returns true if this list changed as a result of the call.

Exception

• IndexOutOfBoundsException − If the index is out of range

• NullPointerException − If the specified collection is null

Adding Multiple Elements to an ArrayList of Integers Example

The following example shows the usage of Java ArrayList addAll(c) method to add Integers. We're adding couple of Integers to the ArrayList object using addAll() method in single statement and then print each element to show the elements added.

package com.tutorialspoint;

import java.util.ArrayList;
import java.util.Arrays;

public class ArrayListDemo {
   public static void main(String[] args) {
      
      // create an empty array list 
      ArrayList<Integer> arrayList = new ArrayList<>();

      // use addAll() method to add elements in the arrayList
      arrayList.addAll(Arrays.asList(10,20,30,40,50));

      // let us print all the elements available in arrayList
      System.out.println("ArrayList = " + arrayList);
   }
}

Output

Let us compile and run the above program, this will produce the following result −

ArrayList = [10, 20, 30, 40, 50]

Adding Multiple Elements to an ArrayList of Strings Example

The following example shows the usage of Java ArrayList addAll(c) method to add Strings. We're adding couple of Strings to the ArrayList object using addAll() method in single statement and then print each element to show the elements added.

package com.tutorialspoint;

import java.util.ArrayList;
import java.util.Arrays;

public class ArrayListDemo {
   public static void main(String[] args) {
      
      // create an empty array list 
      ArrayList<String> arrayList = new ArrayList<>();

      // use addAll() method to add elements in the arrayList
      arrayList.addAll(Arrays.asList("A","B","C","D","E"));

      // let us print all the elements available in arrayList
      System.out.println("ArrayList = " + arrayList);
   }
}

Output

Let us compile and run the above program, this will produce the following result −

ArrayList = [A, B, C, D, E]

Adding Multiple Elements to an ArrayList of Objects Example

The following example shows the usage of Java ArrayList addAll(index, c) method to add a collection of Student objects at particular index. We're adding couple of Student objects to the ArrayList object using add() method calls per element and using addAll(index, E) in the end to add few students at particular location and then printing the ArrayList using its toString() method.

package com.tutorialspoint;

import java.util.ArrayList;
import java.util.Arrays;

public class ArrayListDemo {
   public static void main(String[] args) {

      // create an empty arrayList
      ArrayList<Student> arrayList = new ArrayList<>();

      // use add() method to add elements in the arrayList
      arrayList.add(new Student(1, "Julie"));
      arrayList.add(new Student(2, "Robert"));
      arrayList.addAll(0, Arrays.asList(new Student(3, "Adam"), new Student(4, "Jene")));
      System.out.println("ArrayList = " + arrayList);      
   }
}

class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result −

ArrayList = [[ 3, Adam ], [ 4, Jene ], [ 1, Julie ], [ 2, Robert ]]