Java.util.ArrayDeque.pollFirst() Method

Description

The java.util.ArrayDeque.pollFirst() method retrieves and removes the first element of this deque.Returns null if this deque is empty.

Declaration

Following is the declaration for java.util.ArrayDeque.pollFirst() method

public E pollFirst()

Parameters

NA

Return Value

This method returns the head of this deque, or null if this deque is empty.

Exception

NA

Example

The following example shows the usage of java.util.ArrayDeque.pollFirst() method.

package com.tutorialspoint;

import java.util.ArrayDeque;
import java.util.Deque;

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

      // create an empty array deque with an initial capacity
      Deque<Integer> deque = new ArrayDeque<Integer>(8);

      // use add() method to add elements in the deque
      deque.add(25);
      deque.add(30);
      deque.add(20);
      deque.add(18);        

      // printing all the elements available in deque
      for (Integer number : deque) {
         System.out.println("Number = " + number);
      }
      int retval = deque.pollFirst();
      System.out.println("Element removed is " + retval);

      // printing all the elements available in deque after using pollFirst()
      for (Integer number : deque) {
         System.out.println("Number = " + number);
      }
   }
}

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

Number = 25
Number = 30
Number = 20
Number = 18
Element removed is 25
Number = 30
Number = 20
Number = 18