ArrayDeque addLast() Method in Java

The java.util.ArrayDeque.addLast(Object element) method in Java is used to insert a specific element at the end of this deque. It is similar to the add() method in Java. Syntax:

Array_Deque.addLast(Object element)

Parameters: The parameter element is of the type ArrayDeque and refers to the element to be added. Return Value: The function does not return any value. Exceptions: The method throws NullPointerException if the passed parameter is NULL. 

The Time Complexity of this addLast(Object element) is O(1) i.e Constant.

Below programs illustrate the Java.util.ArrayDeque.addLast() method: 

Program 1: Adding Integers to the Deque. 

Java

// Java code to illustrate addLast()
import java.util.*;

public class ArrayDequeDemo {
    public static void main(String args[])
    {
        // Creating an empty ArrayDeque
        Deque<Integer> de_que = new ArrayDeque<Integer>();

        // Use add() method to add elements into the Deque
        de_que.add(10);
        de_que.add(15);
        de_que.add(30);
        de_que.add(20);
        de_que.add(5);

        // Displaying the ArrayDeque
        System.out.println("ArrayDeque: " + de_que);

        // Adding elements at the end
        de_que.addLast(40);
        de_que.addLast(50);
        de_que.addLast(60);
        de_que.addLast(70);

        // Displaying the ArrayDeque
        System.out.println("ArrayDeque_end_addition: " + de_que);
    }
}

Output:

ArrayDeque: [10, 15, 30, 20, 5]
ArrayDeque_end_addition: [10, 15, 30, 20, 5, 40, 50, 60, 70]

Program 2: Adding String to the Deque. 

Java

// Java code to illustrate addLast()
import java.util.*;

public class ArrayDequeDemo {
    public static void main(String args[])
    {
        // Creating an empty ArrayDeque
        Deque<String> de_que = new ArrayDeque<String>();

        // Use add() method to add elements into the Deque
        de_que.add("Welcome");
        de_que.add("To");
        de_que.add("Geeks");
        de_que.add("4");
        de_que.add("Geeks");

        // Displaying the ArrayDeque
        System.out.println("ArrayDeque: " + de_que);

        // Adding elements at end
        de_que.addLast("GFG");
        de_que.addLast("World");
        de_que.addLast("Hello");

        // Displaying the ArrayDeque
        System.out.println("ArrayDeque_end_addition: " + de_que);
    }
}

Output:

ArrayDeque: [Welcome, To, Geeks, 4, Geeks]
ArrayDeque_end_addition: [Welcome, To, Geeks, 4, Geeks, GFG, World, Hello]