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What is the Deque.getFirst() method in Java?

Sumit Sharma

Grokking Modern System Design Interview for Engineers & Managers

Ace your System Design Interview and take your career to the next level. Learn to handle the design of applications like Netflix, Quora, Facebook, Uber, and many more in a 45-min interview. Learn the RESHADED framework for architecting web-scale applications by determining requirements, constraints, and assumptions before diving into a step-by-step design process.

In this shot, we will discuss how to use the Deque.getFirst() method in Java.

The Deque.getFirst() method is present in the Deque interface inside the java.util package.

Deque.getFirst() is used to retrieve the first element of the deque. If the deque is empty, it throws a NoSuchElementException.

Syntax

Element getFirst() 

Parameters

The Deque.getFirst() doesn’t take parameters.

Return value

The Deque.getFirst() method returns the first element in the deque.

Working example

Let us take a look at the code snippet:

import java.util.*;
class Main 
{
    public static void main(String[] args)
    {
        Deque<Integer> d = new LinkedList<Integer>();
        
        d.add(212);
        d.add(621);
        d.add(23);
        d.add(1280);
        d.add(1171);
        
        System.out.println("Elements in the deque are: "+d);
        System.out.println("The head of the deque is: "+d.getFirst());
    }
}
Using Deque.getFirst() method in Java

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.getFirst() method and displayed the first element in the deque with a message.

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

RELATED TAGS

communitycreator
java

Grokking Modern System Design Interview for Engineers & Managers

Ace your System Design Interview and take your career to the next level. Learn to handle the design of applications like Netflix, Quora, Facebook, Uber, and many more in a 45-min interview. Learn the RESHADED framework for architecting web-scale applications by determining requirements, constraints, and assumptions before diving into a step-by-step design process.

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