Java ArrayDeque Class: removeFirst() Method

public E removeFirst()

The removeFirst() method is used to retrieve and remove the first element of a given deque.

This method differs from pollFirst only in that it throws an exception if this deque is empty.

Package: java.util

Java Platform: Java SE 8

Syntax:

removeFirst()

Return Value:

the head of this deque

Return Value Type: E - the type of elements held in this collection

Throws:

NoSuchElementException - if this deque is empty

Pictorial Presentation

Example: Java ArrayDeque Class: removeFirst() Method

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

public class Main {
   public static void main(String[] args) {
      
      // Create an array deque 
      Deque deque = new ArrayDeque(8);

      // Use add() method to add elements in the deque
      deque.add(100);
      deque.add(200);
      deque.add(150);
      deque.add(95);        

      // Print all the elements of the original deque
      System.out.println("Elements of the original deque:");
      for (Integer number : deque) {
         System.out.println("Number = " + number);
      }

     // Using remove() remove element at the first postion
      int re = deque.removeFirst();
      System.out.println("Element removed is: " + re);


      // Print all the elements available in deque after pushing two elements using removeFirst()
      System.out.println("New deque:");
      for (Integer number : deque) {
         System.out.println("Number = " + number);
      }
   }
}
 

Output:

Elements of the original deque:
Number = 100
Number = 200
Number = 150
Number = 95
Element removed is: 100
New deque:
Number = 200
Number = 150
Number = 95

Java Code Editor:

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