List addAll() Method in Java with Examples (original) (raw)

Last Updated : 02 Jan, 2019

This 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.Syntax:

boolean addAll(Collection c)

Parameters: This function has a single parameter, i.e, Collection c, whose elements are to be appended to the list.Returns: It returns true if the elements of specified list is appended and list changes. Below programs show the implementation of this method.Program 1:

Java `

// Java code to show the implementation of // addAll method in list interface import java.util.*; public class GfG {

// Driver code
public static void main(String[] args)
{

    // Initializing a list of type arraylist
    List<Integer> l = new ArrayList<>();
    l.add(10);
    l.add(15);
    l.add(20);
    System.out.println(l);

    // Initializing a collection to be appended to list
    ArrayList<Integer> arr = new ArrayList<Integer>();
    arr.add(100);
    arr.add(200);
    arr.add(300);
    System.out.println(arr);

    l.addAll(arr);

    System.out.println(l);
}

}

`

Output:

[10, 15, 20] [100, 200, 300] [10, 15, 20, 100, 200, 300]

Program 2: Below is the code to show implementation of list.addAll() using Linkedlist.

Java `

// Java code to show the implementation of // addAll method in list interface import java.util.*; public class GfG {

// Driver code
public static void main(String[] args)
{

    // Initializing a list of type Linkedlist
    List<Integer> l = new LinkedList<>();
    l.add(10);
    l.add(15);
    l.add(20);
    System.out.println(l);

    // Initializing a collection to be appended to list
    ArrayList<Integer> arr = new ArrayList<Integer>();
    arr.add(100);
    arr.add(200);
    arr.add(300);
    System.out.println(arr);

    l.addAll(arr);

    System.out.println(l);
}

}

`

Output:

[10, 15, 20] [100, 200, 300] [10, 15, 20, 100, 200, 300]

Reference: Oracle Docs