RemoveFirst() Method : ArrayDeque in Java

Declaration :

public E removeFirst()

1	public E removeFirst()

Explanation :

Purpose	The java.util.ArrayDeque.removeFirst() method retrieves and removes the first element of this deque.
Parameters	NA
Return Value	This method returns the head (first element) of this deque.
Exception	NoSuchElementException — if this deque is empty.

Java Program : Example

Below example will explain java.util.ArrayDeque.removeFirst() method.

package com.c4learn;
import java.util.ArrayDeque;
import java.util.Deque;
public class ArrayDequeDemo {
   public static void main(String[] args) {
      // Create empty array deque with an initial capacity
      Deque<Integer> deque = new ArrayDeque<Integer>(8);
      // Use add() method to add elements
      deque.add(100);
      deque.add(200);
      deque.add(300);
      deque.add(400);        
      deque.add(500);        
      System.out.println("Deque before : " + deque);
      // Remove elements using removeFirst()
      int val = deque.removeFirst();
      System.out.println("Element removed is : " + val);
      System.out.println("Deque after  : " + deque);
   }
}

package com.c4learn;

import java.util.ArrayDeque;

import java.util.Deque;

public class ArrayDequeDemo {

public static void main(String[] args) {

// Create empty array deque with an initial capacity

Deque<Integer> deque = new ArrayDeque<Integer>(8);

// Use add() method to add elements

deque.add(100);

deque.add(200);

deque.add(300);

deque.add(400);

deque.add(500);

System.out.println("Deque before : " + deque);

// Remove elements using removeFirst()

int val = deque.removeFirst();

System.out.println("Element removed is : " + val);

System.out.println("Deque after : " + deque);

}

Output of Program :

Deque before : [100, 200, 300, 400, 500]
Element removed is : 100
Deque after  : [200, 300, 400, 500]

Deque before : [100, 200, 300, 400, 500]

Element removed is : 100

Deque after : [200, 300, 400, 500]