What is Deque.pollFirst() method in Java?

In this shot, we will discuss the Deque.pollFirst() method in Java. It is present in the Deque interface inside the java.util package.

The Deque.pollFirst() method retrieves and removes the first element from the deque.

Syntax

Element pollFirst()

Paramter

The Deque.pollFirst() method doesn’t take any parameter.

Return

The Deque.pollFirst() method returns:

  • Element: The first element of the deque. It returns null if the deque is empty.

Code

Let’s look at the code snippet given below.

import java.util.*;
class Main 
{
  public static void main(String[] args)
  {
    Deque<Integer> d = new LinkedList<Integer>();
    d.add(286);
    d.add(425);
    d.add(289);
    d.add(410);
    d.add(2971);
    System.out.println("Elements in the deque are: "+d);
    System.out.println("Element removed from deque using Deque.pollFirst() method is: "+d.pollFirst());
  } 
}

Explanation

  • In line 1, we imported the required package.
  • In line 2, we made a Main class.
  • In line 4, we made a main function.
  • In line 6, we declared a Deque consisting of Integer type elements.
  • From lines 8 to 12, we inserted values in the deque by using the Deque.add() method.
  • In line 14, we displayed the original deque elements.
  • In line 15, we used the Deque.pollFirst() method and displayed the removed first element from the deque with a message.

In this way, we can use the Deque.pollFirst() method in Java.

Free Resources

License: Creative Commons-Attribution-ShareAlike 4.0 (CC-BY-SA 4.0)