Java ArrayList addAll() Method Example

ArrayList Methods with Examples

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• Java ArrayList add() Method
• Java ArrayList addAll() Method
• Java ArrayList clear() Method
• Java ArrayList contains() Method
• Java ArrayList ensureCapacity() Method
• Java ArrayList clone() Method
• Java ArrayList get() Method
• Java ArrayList indexOf() Method
• Java ArrayList remove() Method
• Java ArrayList removeAll() Method
• Java ArrayList removeIf() Method
• Java ArrayList retainAll() Method
• Java ArrayList sort() Method
• Java ArrayList spliterator() Method

Java ArrayList Examples

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• Java Convert Array to Set
• Copying part of Array in Java Example
• Sorting an Array using Arrays.sort() Method
• Check Two Arrays are Deeply Equal
• Java Arrays.copyOf() Example - Copying an Array
• Java Arrays.binarySearch() Example - Searching an Array
• Java Arrays.asList() Example - Convert Array to ArrayList
• Java Convert Array to Stack Example
• What's the Simplest Way to Print a Java Array?
• Java Pyramid Examples
• How to Check if Two Arrays are Equal in Java
• Create and Initialize Two Dimensional Array in Java
• How to Initialize an Array in Java in One Line
• Java Array - Create, Declare, Initialize and Print Examples
• Java Array Simple Program

The java.util.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).

Java ArrayList addAll() Method Example

The following example shows the usage of java.util.ArrayList.addAll(c) method:

import java.util.ArrayList;

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

      // create an empty array list1 with an initial capacity
      ArrayList<Integer> arrlist = new ArrayList<Integer>(5);
      
      // use add() method to add elements in the list
      arrlist.add(12);
      arrlist.add(20);
      arrlist.add(45);

      // let us print all the elements available in list1
      System.out.println("Printing list1:");
      for (Integer number : arrlist) {
         System.out.println("Number = " + number);
      }

      // create an empty array list2 with an initial capacity
      ArrayList<Integer> arrlist2 = new ArrayList<Integer>(5);
      
      // use add() method to add elements in list2
      arrlist2.add(25);
      arrlist2.add(30);
      arrlist2.add(31);
      arrlist2.add(35);

      // let us print all the elements available in list2
      System.out.println("Printing list2:");
      for (Integer number : arrlist2) {
         System.out.println("Number = " + number);
      }

      // inserting all elements, list2 will get printed after list1
      arrlist.addAll(arrlist2);
      
      System.out.println("Printing all the elements");
      // let us print all the elements available in list1
      for (Integer number : arrlist) {
         System.out.println("Number = " + number);
      }
   }
}

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

Printing list1:
Number = 12
Number = 20
Number = 45
Printing list2:
Number = 25
Number = 30
Number = 31
Number = 35
Printing all the elements
Number = 12
Number = 20
Number = 45
Number = 25
Number = 30
Number = 31
Number = 35