Java.util.ArrayDeque.offerFirst(E) Method

Description

The java.util.ArrayDeque.offerFirst(E e) method inserts the specified element E at the front of this deque.

Declaration

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

public boolean offerFirst(E e)

Parameters

• e -- The element to be added at the front.

Return Value

This method returns true if the element was added to this deque, else false.

Exception

• NullPointerException -- if the specified element is null.

Example

The following example shows the usage of java.util.ArrayDeque.offerFirst() 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);        
           
      // this will insert 10 at the front
      deque.offerFirst(10);

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

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

Number = 10
Number = 25
Number = 30
Number = 20
Number = 18