What is the ArrayDeque.pop method in Java?

An ArrayDequeArray Double Ended Queue is a growable array that allows us to add or remove an element from both the front and back.

This class is the implementation class of the Deque interface. ArrayDeque can be used as a stack or queue. Null elements are prohibited.

What is the pop method of ArrayDeque?

The pop method can be used to get and remove the first element of the ArrayDeque object.

Syntax

public E pop()

Parameters

This method doesn’t take any parameters.

Return value

The pop() method retrieves and removes the first element of the deque object. If the deque object is empty, then NoSuchElementException is thrown.

This method is the same as the removeFirst method.

Code

The code below demonstrates how to use the pop method.

import java.util.ArrayDeque;
class Pop {
    public static void main( String args[] ) {
      ArrayDeque<String> arrayDeque = new ArrayDeque<>();
      arrayDeque.add("1");
      arrayDeque.add("2");
      arrayDeque.add("3");
      System.out.println("The arrayDeque is " + arrayDeque);
      System.out.println("arrayDeque.pop() returns : " + arrayDeque.pop());
      System.out.println("The arrayDeque is " + arrayDeque);
    }
}

Explanation

In the above code:

  • In line 1: We import the ArrayDeque class.

  • In line 4: We create an ArrayDeque object with the name arrayDeque.

  • From lines 5 to 7: We use the add() method of the arrayDeque object to add three elements ("1","2","3") to dequeu.

  • In line 10: We use the pop() method of the arrayDeque object to get and remove the first element. In our case, 1 will be removed and returned.

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