What is the ArrayDeque.push 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 push method of ArrayDeque?

The push method can be used to add an element to the beginning/front of the ArrayDeque object.

Syntax

public void push(E e);

This method takes the element to be added as an argument. If the argument is null, then a NullPointerException is thrown.

This method doesn’t return any value.

Code

The code below demonstrates how to use the push method.

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

Explanation

In the code above:

  • In line 1, we import the ArrayDeque class.

  • In line 4, we create an ArrayDeque object with the name arrayDeque.

  • In line 5, we use the push method of the arrayDeque object to add an element ("3") to the beginning of the deque and print it.

  • In line 8, we use the push method to add an element ("2") to the beginning of the deque and print it.

  • In line 11, we use the push method to add an element ("1") to the beginning of the deque.

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